London Loop 11/12: Hayes (Hillingdon) - Uxbridge - Harefield

Horton Bridge, Grand Union Canal

THIS WALK FIRST HEADS WEST, towards the Colne Valley Park, then north through the park along the valley itself, essentially following the Grand Union Canal. It’s one of the greenest and bluest sections of the London Loop, almost entirely off-road and largely beside water. It’s also arguably one of the least varied, although there are some diversions to provide a respite from towpath walking: through the odd blend of business centre and country park at Stockley, around some placid lakes set among woodland, and along the river Colne itself.

This is another concatenation of two official Loop sections, creating a relatively long walk, though as it’s along well-defined paths in flat country, you should make good time. The official break point is Uxbridge, particularly convenient as it’s on the Tube, but there are several other places with bus connections, including the end point which, rarely for the Loop, is at a bus stop rather than a station.

A short path between Stockley Park and Horton, now mentioned in the text below as an update, has made this section even more traffic-free. Another alternative option, which you might want to consider if rewalking the Loop or as a walk in its own right. The Hillingdon Trail leaves the Loop on the Grand Union Canal near Bulls Bridge and finds its own way along the Yeading Valley, rejoining the Loop at Harefield. It's rather a longer option, though, so might be best split into two walks.

Grand Union Canal

Grand Union Canal milepost at Hayes. The abbre-
viation refers to the Grand Junction Canal Co.

Following a brief taste on the previous walk, you’ll find yourself alongside the canal for much of this section, so now is the time to say a bit more about it. The practice of digging artificial water channels as a form of transport infrastructure dates back at least to Roman times, though the current network of canals in the UK is largely a product of the Industrial Revolution. Prior to this, transporting bulk goods long distances inland to destinations that weren’t close to the navigable sections of natural rivers involved horse-drawn wagons, rendered even slower and more laborious by the poor state of the roads.

The practice of improving rivers for navigation by dredging, removing obstructions, straightening courses and constructing locks and weirs to manage level changes also has a long history. As we’ve already seen along the Thames on the London Countryway, these activities increased during the 16th and 17th centuries with the development of trade. And digging an entirely artificial channel between two places not previously connected by water is very much like digging a cut to avoid the meanderings of a river, but on a grander scale.

With the emergence of large scale industry in the mid-18th century the need for bulk transport increased massively. Previously, large settlements had tended to grow in places that already had decent transport links like navigable rivers or coasts, but the location of the new industrial centres was dependent instead on their proximity to crucial resources like coal and iron, and many were deep inland. And with railways and powered vehicles still some decades away, new canals were the obvious solution.

The first true modern canal in the UK was the Newry Canal in Ulster, opened between the Tyrone coalfields and the Irish Sea near Newry in 1742. The first entirely artificial canal in England was the Bridgewater Canal, the first stretch of which opened between the Worsley coal mines and Manchester in 1761. The success of these and other projects sparked a boom in canal construction lasting some 60 years, helping transform the face of the country, particularly in the Midlands and north of England.

As with the railways that were to follow, the canals were almost entirely built as private commercial ventures under the authority of individual Acts of Parliament which among other things gave their builders the necessary powers to purchase land and to charge tolls to users. And like the railways, the result was a tangled and sometimes irrational network of competing routes. Most were ‘narrow canals’ with a minimum width of only seven feet (2.1 m), as these were cheaper to construct, and a new style of long, thin ‘narrowboats’ emerged to navigate them. Originally these boats were unpowered, towed by horses walking along a parallel towpath, and some of them remained so into the 20th century.

Birmingham, as is well-known, has more canals than Venice, but until the very end of the 18th century the only waterway connection between the West Midlands and London followed the Oxford Canal to its namesake city and then the Thames. Despite numerous improvements, the river was much less amenable to boats than a purpose-built canal and, with its natural meanders, notably indirect.

A number of possible routes were surveyed and in 1793 Parliament approved a proposal by the Grand Junction Canal Company. This created a new link from Braunston in Northamptonshire, on the Oxford Canal much closer to Birmingham, with the Thames at Brentford, then still a separate town west of London, shortening the journey by about 100 km. The 150 km Grand Junction was built as a broad canal with a minimum width of 14 feet (4.2 m) but the connecting Oxford Canal was narrow, so only narrowboats could make the through trip.

For some reason, MPs had preferred the Brentford route to a competing proposal direct to central London, but it wasn’t long before the wisdom of this was questioned. In 1795, with construction only just started, Parliament approved a 22 km branch from Bulls Bridge, a few steps from where the Loop first joins the canal in the previous section, to Paddington. The railway station for which this northwest corner of central London is now best known was still some decades away, but it was already a transport interchange as the western end of the New Road (today’s Marylebone, Euston, Pentonville and City Roads), London’s first bypass, opened to the City in the 1750s.

Constructed under the direction of the celebrated canal engineer William Jessop, the waterway opened in stages. The section from Brentford to Hemel Hempstead, which the Loop follows, opened in 1798, followed by the Paddington Arm in 1801. The complete route was delayed until 1811 by problems with a tunnel nearer to Braunston. By then the Warwick & Napton and Warwick & Birmingham canals, both opened in 1800, had created an even more direct route from Braunston to Birmingham. Connections were further improved with the opening by a separate company of the Regents Canal between 1816-20, providing a direct waterway link from Paddington to Limehouse in the London Docklands.

At first, perhaps unsurprisingly given the economic powerhouses it connected, the canal was hugely successful. In 1810, almost 350,000 tonnes of goods were transported along the waterway to London, and in 1831 it generated £160,000 in tolls – about £15 million in today’s prices. But in 1825 the UK’s first steam-operated railway, the Stockton and Darlington, heralded the arrival of a means of transport that was to change the landscape once again. In 1838 the UK's first intercity railway provided an alternative link between London and Birmingham, placing the Grand Junction on the sharp end of railway competition.

The commercial decline of the canal network was a prolonged process which was never quite completed, as a modest (and modestly growing) amount of freight still travels this way today. The arrival of steam power in the 1860s helped, but the only real way for the canals to compete was by lowering tolls, which meant cutting maintenance costs, in turn generating problems with safety and reliability. In 1929 the Grand Junction company merged with the Warwick canals into a group led by the Regents Canal company, with the whole length between London and Birmingham renamed the Grand Union. The new group launched a refurbishment and widening programme financed by government loans. But by then the arrival of further competition in the form of road transport had tightened the screws on the canal system still further.

The end of World War II ushered in a brave new world of state planning, and in 1948 much of the canal system, including the Grand Union, was nationalised along with the railways under the British Transport Commission, succeeded in 1963 by the British Waterways Board. By now some far-sighted people had started to rethink the waterways in terms of other purposes, such as recreation and the environment. The decline of commercial traffic created space for leisure cruisers, day trips, house boats and anglers, while towpaths once trodden by labouring horses provided a potential network of easy off-road routes for walkers and cyclists. Newly clean canals turned out to be havens for wildlife, not only in the water but in the grassy margins which provided green strips through urban areas.

Pressure groups such as the Inland Waterways Association, formed in 1946 following the publication of Tom Rolt’s influential book Narrow Boat, campaigned for this sort of repurposing, with a wave of volunteer-led projects to restore canals that had been abandoned as uneconomic. Initially the navigation authorities were unsympathetic to alternative uses, but this stance shifted as it became clear that commercial traffic was a lost cause, and the 1968 Transport Act explicitly recognised the leisure potential of waterways. Another financial lifeline has emerged more recently: many towpaths now host fibre optic cables and even high tension mains.

Grand Union Canal just south of Swan and Bottle Bridge

The cultural transformation of the waterways from utilitarian necessity to environmental asset has been dramatic. Before the second half of the 20th century few people would have visited urban canals unless they had to – they were smelly, dirty, dangerous places, particularly neglected ones that had become informal rubbish dumps. People who worked on them were regarded as a race apart. The families of boating operators usually lived on their boats, always on the move, and for generations missed out on education and literacy, becoming an isolated and inward-looking underclass. They developed their own culture, expressed among other ways in the traditional decorations of their boats. Now that culture remains only as an appropriated emblem of heritage, and middle class alternative lifestylers pride themselves on the castles and roses brightening their wifi-equipped narrowboats.

This transformation is written in the pattern of development. Most buildings more than a few decades old in the immediate vicinity of the waterway are industrial. Older residential properties either turn their back on the water or stay at a safe distance. New developments, in contrast, embrace the canal as a positive feature, with properties closer to the water sold at premium pirces. There’s a good example of this approaching Harefield West, where luxury designer dwellings overlook what was once a clogged artery of the Industrial Revolution.

British Waterways, meanwhile, succumbed to the contemporary political distaste for state agencies in 2012, when its assets, including the Grand Union, were handed to a new independent charity, the Canal & River Trust. Currently the Trust enjoys continuing government funding but its long term sustainability remains to be proved, and there may yet be another crisis period for the waterways.

Planning a canal route meant balancing several factors including directness, the cooperativeness of landowners, and geography. Canals aim to be as level as possible so the flow of water is kept to a minimum; any significant change in level requires the use of locks, which are expensive to engineer and maintain and slow progress for boats. One solution is to follow river valleys, also providing a nearby source of water, and the Grand Union adopts this strategy in several places. At Brentford it’s essentially a canalised section of the river Brent for a while, but the Loop joins it where it traverses river valleys to pick up the river Colne. The bridges are all numbered and the sequence starts in Braunston so we follow it in reverse, starting at number 200, Station Road Bridge in Hayes.

Stockley Park

The view from Stockley Park

Canal walking isn’t to everyone’s taste. Well-defined towpaths with the minimum of sharp turns make for easy progress, with passing boats and wildlife for interest, and in an urban area there’s an odd sensation of alternative geography, of hidden threads stitched within the fabric of familiar streets. But the lack of challenge and the consistency of the surroundings can make you yearn for a bit more variety. The Loop responds by not sticking religiously to the towpath, instead heading off on intermittent detours to show you more of your surroundings.

There are also a number of diversions you could make yourself. Soon after rejoining the towpath, a Legible London-style sign points off to the Old Vinyl Factory, the former EMI record plant discussed at the end of the last section. EMI also has a connection to Lake Farm Country Park on the right, as between the late 1940s and early 1990s it tested radar equipment here. A testing tower, concrete surfaces, a derelict trailer and other remnants still stand on a site that has also been a common, a brickworks and, more recently, hay meadows.

Hillingdon Council bought Lake Farm in 1998 following a local campaign to save it as open space, installing among other things a much-loved sculpture of a skylark by Ben Dearnley, later one of the official artists for London 2012. There was another local storm in 2014 when the council authorised the building of an academy primary school in the northeast corner.

The first official detour starts just a little way further along, venturing through an even more intriguing space that’s also associated with the brick industry. What’s now Stockley Park was once arable land and later cattle pasture, until the 1650s when then-owner John Bennet, Charles II’s deputy postmaster, had it inclosed as a deer park, gardens and ‘furze ground’ where gorse was grown as winter fodder for deer – this last is commemorated in a contemporary street name, Furzeground Way.

That all changed when the excavation of the canal uncovered a particularly fine source of brick earth, as well as providing a convenient means for transporting it. Bricks made here were used among other things in the building of Kensington museums; known as Cowley Stocks, they eventually gave rise to the current name.

Following the exhaustion of the brick earth in the early 20th century, the site was used for gravel extraction and then for landfill, leaving a polluted wasteland. An ambitious redevelopment scheme for the 180 ha site was launched in 1985, creating the present prestigious, hi-tech business park with its innovative architecture set among lakes, public green space and a golf course, finally opened in 1993. Among the tenants are such weighty international names as Apple, BP, Canon, and GlaxoSmithKline, attracted both by the amenities and the closeness to Heathrow Airport.

This was a major landscaping project, with four million cubic metres of rubbish, clay and gravel transported over 18 months from the business park zone in the south, nearest the canal, and used to shape the surrounding green spaces. New topsoil was created artificially on site by mixing local clay with imported manure, seeding and ploughing back in the initial grass crops, and introducing over one million earthworms.

Suspension bridge, Stockley Country Park

It’s an odd place to walk around, with even its parkland and water features self-evidently designed to complement striking buildings by leading architectural practices like Fosters and Arup – a little like a vision of the future from a 1960s film. The oddness is accentuated by the fact that all the buildings are for business use: apart from a Wetherspoon pub, a gym, a couple of shops and the golf course clubhouse, they’re all offices, warehouses and wokshops. The master plan was prepared just as planners’ preference for strict land use zoning was going out of fashion, and had it been delayed by a few years, housing would surely have been included in the mix, creating a more lived-in feel.

That said, it’s attractive in its own way, and the effort put into creating the green space is praiseworthy. The Loop passes the remains of the dock that once served the brickworks, now a water feature, and soon picks up a precisely regimented avenue of lime trees, intended to invoke the formal gardens of John Bennet’s time. If you follow these to the end, you’ll find the hub of the site, where the pub and shops overlook a lake, but the Loop heads off on a track shielded from the golf course by a substantial hedge to cross a landmark suspension bridge which links the two halves of the site across a bisecting road. Further development is currently taking place on a northern extension of the business park here.

On the other side the trail passes close to a viewpoint atop a grassy hill which, thanks to all that topsoil engineering, displays no clue of its true nature as the biggest pile of rubbish in the park. From here there are views towards the Colne Valley and Chilterns as well as of the comings and goings at Heathrow, from a more comfortable distance than experienced on the previous section.

Another hedge-lined track successfully conceals not just the golf course on one side but the grounds of Uxbridge Football Club on the other before returning you to the road and to a much older industrial area, where expanses of giant utilitarian sheds bearing rather less glamorous names spread backwards from the canalside, punctuated by the occasional residential terrace.

Along Horton Bridge Road, the Brickmakers pub, currently abandoned, recalls in its name the once-favoured local industry. Opposite is the John Guest factory, a name well-known to plumbers as a leading manufacturer of valves and connectors. The Loop rejoins the canal at Horton Bridge itself, still one of the original quaint humped white bridges, bearing the number 193.

Update October 2017. A new path, Weston Walk, opened early in 2017 in connection with a new development, now provides a direct connection from Stockley Park to the towpath near Horton Bridge, with no need to follow roads through the industrial area. I've updated the route description to include both options. Read more here.

West Drayton and the Slough Arm

Cowley Peachey Junction: the Grand Union running left to right and the Slough Arm in the background. Packet Boat
Marina is behind the grass bank top right.

The next bridge, Colham Bridge, carries West Drayton High Street, with an option to duck out at the similarly named station, the next one down from Hayes & Harlington on the Great Western Main Line, discussed in the last section. It’s here that the canal and the Loop start to bend north, tracking the contour of the Colne valley. The waterway marks the division between Yiewsley, to the north, and West Drayton to the south. The latter began as an ancient Middlesex parish, one of the westernmost in the county, bounded by the river Colne which long divided it from Buckinghamshire. The name likely indicates a place where boats were dragged to and from the river.

For much of its history, it was a rather isolated agricultural village with a few small mills, and there are still 17th and 18th century houses, mainly clustered around the old village centre now known as the Green, a conservation area to the southwest. Visiting train travellers in the late 1830s could still find geese, pigs and donkeys on the green, but industry had already colonised the canalside and the railway soon generated a new suburb spreading out from the station, where you’ll find most of the shops and services today. James Thorne’s Handbook to the Environs of London in 1876 observed how the village's remaining rural charms were undermined by “sulphurous and manury smells from brickfields, canals, and wharves.”

Another trail, the 26 km Beeches Way, starts at West Drayton station and briefly runs along with the Loop. The Way was a Buckinghamshire initiative, one of a number of signed walking routes in the county developed in the 1970s and 1980s by Ramblers and voluntary groups working with the council. It actually starts just in London and finishes just in historic Berkshire, at Cookham in the Royal Borough of Windsor and Maidenhead. It’s so named because it crosses Burnham Beeches, one of the City of London-owned green spaces outside Greater London itself. Among other things it provides a signed link between the London Countryway and the London Loop, and with the Grand Union Canal forms a short cut between two points on the Thames Path, at Brentford and Cookham.

There’s one more bridge, the picturesquely named Trout Road Bridge, and a swathe of recent waterside development, to go before the next diversion, although for a while at least this is also along a towpath. At Cowley Peachey Junction, a branch canal, the Slough Arm, leaves to the west. Several contrasting environments meet here. To the southwest are the wooded wetlands of the Colne Valley Park. Opposite, on the north side of the Slough Arm, is Packet Boat Marina, opened on the site of another contaminated gravel pit in 2003 and now bright with the colours of privately owned narrowboats. To the right, east of the Grand Union, is a retail park boasting the likes of Argos, Curry’s and a giant Mercedes Benz dealership.

The marina is named after the lane on which it stands, which in turn is named for the ‘packet boats’ that once plied the canals alongside more familiar narrowboats carrying bulk goods. The packets in question were small parcels, but the boats were better known for carrying passengers. Indeed they were one of the earliest forms of mass public transport, running to a published timetable. In the early 19th century a packet boat service departed daily from Uxbridge to Paddington and vice versa, but was never a great success as the journey took too long, so was soon supplanted by rail and road improvements.

The 8 km Slough Arm was one of the last canals to be built in Britain, opened in 1882, long after the early 19th century boom. Its main purpose was to carry bricks and other building materials from new brickworks at Slough to the ever-expanding building sites of London. But as the raw materials were exhausted, traffic steadily declined from a peak in 1905, with commercial use ceasing in 1960, after which it was left to decay. British Waterways initially classified it as a ‘remainder canal’, slated for closure, and Slough council proposed to fill in and build on part of it, but it was saved by a local campaign and reopened in 1975. Today there’s even an ambition to extend it by 3 km through Slough town centre to connect with the Thames, though with no funding currently assigned.

Frays River, visible bottom left, with the Slough Arm crossing it on an aqueduct and a World War II pillbox beyond.

It’s always fun when one waterway crosses another on an aqueduct, and the Slough Arm has three such examples, although the Loop only stays with it long enough to encounter one. This is the crossing of the Frays River, actually a loop of the Colne between West Drayton and Uxbridge. Its exact history is unknown but it is likely at least semi-artificial. It takes its name from a 15th century landowner, John Fray, but long predates its namesake: it could have been dug as far back as late Saxon or early Norman times to feed mills at Uxbridge. Just beyond it a World War II pillbox still stands beside the canal.

The Loop leaves the Slough Arm at the next bridge, a lovely spot where Trout Lane, now little more than a footpath, crosses the canal and heads deep into the green surrounds of the Colne Valley Park.

Colne Valley Park

Gulls wheel over Little Britain Lake, Colne Valley Park

The Colne Valley is one of London’s two long-established regional parks. The other, the Lee Valley Park on the other side of the city to the east, is also draped about a major Thames tributary running roughly north-south (a third regional park, the Wandle Valley Park, is now being developed along another Thames tributary in southwest London, this time running south-north). These two stand almost like bookends to the capital: both straddle the boundary and include parts of neighbouring counties, except that while the Colne Valley clings to the rim of suburbia, the Lee Valley digs deep into the inner city, between Bow and Stratford.

The eastern park’s more urban character and its proximity to a denser population might explain why it’s rather better-known and better-supported than its western counterpart. Certainly, its open spaces seem all the more miraculous. But the Colne has much to offer too, with numerous surprisingly quiet and secluded places within easy reach of transport, and its own role in determining the texture of the edge of London.

Both parks share a legacy from rich deposits of gravels laid down in the last glacial period, quarried millennia later as building materials to service London’s physical growth. As the gravels became exhausted the workings were abandoned, leaving behind an inhospitable and dangerous landscape of often polluted pits. But as the demand for outdoor recreation and green space for London grew, these wastelands were reimagined. Initially their main value was assumed to lie in water-based activities like fishing and boating, but tree-lined banks also made ideal spaces for walking, cycling, playing and enjoying nature.

As discussed in some detail in my account of the London Countryway, the idea of regional parks followed on from the National Parks created by postwar legislation. The latter were designated because of the character of their countryside, irrespective of their location, while regional parks, which never gained statutory recognition as a category, were specifically intended to serve big city populations.

The Lee Valley Park was first envisioned in Patrick Abercrombie’s utopian Greater London Plan of 1944, but only eventually happened because of the determination of local campaigners. Abercrombie only mentioned the Colne in passing, commenting on its numerous channels, but proposals for the Lee surely inspired a 1965 report by Hillingdon council noting the recreational potential of numerous abandoned gravel pits along the river. This report, and support from the Greater London Council, resulted in a conference of the various local authorities concerned later that year, and the park began to take shape in the 1970s.

The official source of the Colne is an underground stream that emerges at North Mymms in Hertfordshire: some of the water surfaces from the swallow holes which the London Countryway passes on its way to Welham Green. But the drainage basin stretches far into the Chilterns, fed by chalk streams like the Chess, Gade, Misbourne (the source of which is also on the Countryway at Great Missenden) and Ver. It has a watershed to the north of Tring with the next great river basin north, the Great Ouse, which drains towards the Wash. The Colne, as already mentioned, runs roughly north-south, joining the Thames at Staines on Thames.

The initial plans for the park covered just over 10,000 ha, since expanded to the current 11,130 ha. It’s a strip of land running from the fringes of Chorleywood and Rickmansworth in the north to Staines, stretching to the Chalfonts, Gerrards Cross, Slough and Datchet in the west and Harefield, Ruislip, Uxbridge and Heathrow in the east. Most is in Buckinghamshire, with parts in Hertfordshire and the London Borough of Hillingdon and small portions in Surrey and Slough (formerly Buckinghamshire, then Berkshire, now a unitary authority).

While its eastern sister has the advantage of a statutory authority with modest fundraising powers, set up by its own Act of Parliament, the Colne Valley Park has always been a more informal partnership between councils, land managers and voluntary groups, which might explain its more sporadic levels of support and its relatively weak identity. It has coped with the age of austerity by creating a Community Interest Company, set up in 2012, which commissions the environmental charity Groundwork to manage the park. The broader vision of a large, connected stretch of public space seems to have been put on hold in favour of concentrating on a number of key sites, some of which we’ll pass on today’s walk.

The history of the park’s own flagship walking trail is symptomatic of the stop-start approach. In the late 1980s, a trail called the Colne Valley Way from Staines to Uxbridge was signed on the ground and promoted in free leaflets. Subsequently, though, it was rather neglected, and in the early 2000s the park management announced it would be superseded by a new route for riders and cyclists as well as walkers running the whole length of the park to Rickmansworth, with branches to other transport interchanges, known as the Colne Valley Trail. But though this is now signed in various places, it hasn’t been completed to the promised extent, and neither trail has a proper description on the park website.

It’s all very confusing, particularly as other trails, including the Loop, Grand Union Canal Walk and various circular walks, share some of the paths used. The Way and the Trail combined, incidentally, effectively form part of an alternative western waterside route for the Loop, by continuing upstream on the Thames Path from Kingston to Staines and then turning north.

Trout Lane leads to the southwest corner of Little Britain Lake, a typical example of one of park’s reclaimed gravel pits and a well-known local beauty spot. Originally dug in the 1930s between the Colne and Frays River, the pit was turned into the current 6 ha lake in the 1970s and first operated as a private fishery, but since 1983 the site has been managed by Hillingdon council as a public space and a designated site of local importance for nature conservation, with an accessible path added in 2005. The islands are largely artificial, created with local hornbeam, birch and willow wood to attract water birds. The name refers to the lake’s supposed similarity in shape to Great Britain, at least as reflected in a mirror, and with a very liberal definition of similarity.

Just inside Buckinghamshire, alongside the river Colne north of Little Britain Lake.

Not far from the lake, the Loop crosses the river Colne itself, and briefly enters the district of South Buckinghamshire, continuing north on a delightful woodland path along the river’s west bank. The county can trace its history back to Saxon times when it was part of the Kingdom of Wessex – specifically, that part that looked to the fortified borough of Buckingham, in the north of the present county, for defence against the Danes. The name derives from an Anglo-Saxon personal name, Bucca, meaning ‘the shire of Bucca’s home’, though the county town has been Aylesbury since Henry VIII’s time. Both the county council logo and the official coat of arms feature swans, apparently because the birds were once bred in the county for the royal dinner table, and you’re bound to encounter a few live examples on this very watery walk.

Coal post on the present London boundary, at Clisby's
Bridge near Iver.

The path crosses back to the Hillingdon side of the river along Iver Lane at Clisby’s Bridge, rebuilt in 1840. On the left just past the bridge parapet is the first surviving City of London coal tax post actually on the trail itself (though we passed close to a couple on Coulsdon Common, and they’re discussed in more detail on the London Countryway).

It was placed here in 1861 when this part of what was then Middlesex was included in the Metropolitan Police District, and is one of a few such posts that now stand on the contemporary boundary of London. The inscription “ACT 24&25VICT CAP42” refers to the legislation that defined this boundary, The London Coal and Wine Duties Continuance Act 1861, by the years of Queen Victoria’s reign in which it was passed, and the chapter number.

Uxbridge

The next stretch of path has been recently widened and surfaced and is easy going, with the green-clothed river on one side, but with industry in the form of the daftly named Chiltern Business Village (not really in the Chilterns, not really a village) on the other. It’s part of a broader industrial area known as Uxbridge Moor, which once was indeed an open area of rough ground on the edge of Uxbridge town until the canal was dug through it. Warehouses, oil and mustard mills, glass and gas works followed. Today the industry is lighter, though there’s still a sizeable paint and coatings plant run by Trimite.

The path bends east away from the river and the Loop follows an industrial estate drive, then narrow Culvert Lane, lined on one side with what once were modest workers’ cottages but are now desirable properties. The eastern section of the street forms part of Uxbridge Moor Conservation Area. Opposite the end of Church Lane, a path on the left will give you a glimpse of St John’s church, a simple but elegant Commissioners’ Church built of local brick in 1838 to a design by Henry Atkinson to serve the expanding population. It was closed in 1993 and the building converted to offices and flats.

Uxbridge Boat Centre at Uxbridge Moor dates back to the Victorian heyday of commercial traffic on the canal.

Culvert Lane takes the Loop back to the canalside, diagonally opposite Uxbridge Boat Centre. Back in the 1880s this was a boatyard belonging to West Bromwich-based Fellows, Morton & Clayton, who became one of the biggest and best-known commercial carriers on the canals. The company continued to build and repair boats here until its liquidation in 1948. After this the yard fell into dereliction until rescued in the 1970s to serve growing leisure traffic, incorporating a traditional chandlery.

Fake art deco: the Parexel Building at Swan and Bottle Bridge, Uxbridge

From here the towpath continues under Dolphin Bridge to Swan and Bottle Bridge, where the old Oxford Road crosses the canal on its way out of Uxbridge. It’s named after the adjoining pub, now in a modern building but with a history as a coaching inn dating back to at least the 1760s. The name likely derives from a merger of two adjoining pubs, the Swan and the Leather Bottle.

The Paraxel building on the other side of the canal from the pub looks at first glance like 1930s art deco but is actually a 1991 pastiche built for a pharmaceutical testing company based in Boston, Massachusetts. Look out also for an attractive partly-mirrored Millennium mosaic under the bridge itself.

Swan and Bottle Bridge marks the official end point of section 11 of the Loop and a signed link from here follows the Oxford Road into Uxbridge town centre. In fact the site of the bridge from which the town takes its name is a few steps in the opposite direction from the Swan and Bottle, where the main road crosses the Colne. The ‘Ux’ is derived from a Saxon personal name, Wixan, although the bridge itself is known as High Bridge. Unsurprisingly given the proximity of the river, human habitation in the area dates back a long way – the excavation of the Chimes shopping mall in the town centre in the late 1990s unearthed Bronze Age remains.

Uxbridge is an important local shopping centre, but do try to avoid pushing
your trolley into the canal.

Uxbridge isn’t mentioned in the Domesday survey, but by around 1200 there was already a chapel of ease of Hillingdon church standing on the Oxford Road. This grew into St Margaret’s Church, which has a 14th century tower and 15th century nave, though is much rebuilt.

Uxbridge then was simply an outlying hamlet of Hillingdon but gradually became an important town in its own right, boosted by traffic on the road (the town boasted 20 inns in 1648), a market established by the late 12th century, and later by industry, including flour milling. Today the reversal of roles is complete: Uxbridge is the administrative centre of the London Borough of Hillingdon, and one of the biggest shopping and commercial centres in outer west London.

The town once had three railway stations: Vine Street (1856), on a branch from the Great Western, closed in 1962 as an early victim of the ‘Beeching Axe’; Belmont Road, opened by the Harrow and Uxbridge Railway as a branch from the Metropolitan Railway in 1904; and High Street (1907) on a branch from the Chiltern Line, closed to passengers in 1939 and closed completely in 1964. Belmont Road was replaced in 1938 by the current London Underground station a little to the south. This station on the Tube’s western extremity survives today, a large and splendid red brick building designed by celebrated Underground architect Charles Holden, with spectacular stained glass friezes above the ticket hall. It’s a fitting place to end your Loop walk if you choose.

Denham

Denham Deep Lock

Pushing on, just beyond Swan and Bottle Bridge, the Colne merges briefly with the canal, and the Buckinghamshire boundary swings in to cross the towpath and follow another branch of the Colne, known, for obvious reasons, as the Shire Ditch. So Denham Yacht Station, with its vaguely boat-shaped single storey building, is actually in Denham, the first parish on the other side, in Buckinghamshire. But then, confusingly, so is Uxbridge Lock, the first canal lock encountered on the Loop, and the only one in South Buckinghamshire District.

The area to the west of the lock, between the canal and another loop of the Colne, was historically the site of two flour mills, the Old Mill and the New Mill, the latter built over an older facility known as Hubard’s Mill in 1835. The site, which includes a fine 18th century mill owner’s cottage, is sometimes known as King’s Mill, not for any royal connections but after a former proprietor, William King. Milling on the site only finally ceased in 2001 but the brand of sliced bread that originated here can still be found in every supermarket.

The Colne leaves the canal again to the left just before both pass under a long, low viaduct that carries the A40, the modern day successor of the Oxford Road, over the valley. This section is part of Western Avenue, the 1930s arterial road running west from White City, but has been widened and rebuilt since. The towpath now runs between the canal and the river, the latter never far away on the left, towards Denham Lock, soon with Denham Country Park beyond. Here the river Misbourne joins the Colne, and a few paces further north the Loop completes the second and last of its brief sidesteps into Buckinghamshire, returning to Hillingdon for the rest of the section.

Denham also has an Anglo-Saxon name, from ‘dene-ham’, settlement in a valley. It appears in the Domesday survey, and between the 13th century and the Dissolution in 1540 it was an important village just off the Oxford Road which was largely the property of Westminster Abbey. The historic village centre is westwards along the Misbourne, while the station, opened in 1906 on what’s now the Chiltern main line, is some way to the northwest, surrounded by its own suburb, Denham Green.

The village is probably best known today for its association with the film industry, which naturally gravitated to the leafy fringes of west and northwest London. While Elstree, further along the Loop, has the strongest claim to being the ‘British Hollywood’, Denham Studios, founded by legendary Hungarian producer Alexander Korda in 1936, produced numerous British classics, including Michael Powell and Emeric Pressburgers’s A Matter of Life and Death (1946) and Laurence Olivier’s Henry V (1944). Film production ceased after 1952, and in the late 1970s the site was redeveloped as an industrial estate known as Broadwater Park. It’s some way off our walk to the northwest – if you want to visit, Widewater Lock, further along the towpath, is the more convenient point to make a detour.

The country park is a fragment of the old manorial estate of Denham Court, which was split up in 1670. The southern part, along the Misbourne, was attached to a fine 17th century mansion, Denham Place, possibly on the site of the original manor house and still standing today at one end of the old village. Poet John Dryden was a frequent visitor in the 1690s and described the place as “one of the most delicious spots in England.” Despite mainly being in Buckinghamshire, the estate was bought in 1936 by Middlesex County Council and inherited by the Greater London Council, transferring to Buckinghamshire on the GLC’s abolition in 1986. Another mid-17th century mansion, now known as Denham Court, stands to the north, closer to the Colne. Following a period of postwar neglect, since 1992 this has been the clubhouse of a prestigious golf course created by Japanese brewery Asahi.

A path to the left just before the lock leads across the Colne and through the country park to Colne Valley Park Visitor Centre about 10 minutes away – it’s a worthwhile detour if you’re after information about other features of interest in the area.

This path is also the start of the South Bucks Way, one of the early routes pioneered by keen walking volunteers in the county from the 1970s. This largely follows the Misbourne Valley for 37 km from Denham Lock to Coombe Hill on the Ridgeway National Trail, in the Chilterns west of Wendover. From here if you dodge a little way along the Ridgeway to Great Kimble you’ll find the start of the North Bucks Way to Wolverton near Milton Keynes, which in turn is the southernmost of a connected series of walks known as the Midshires Way, north through Middle England to Manchester with connections to the Pennine Way. So from Denham Lock you could if you wished walk signed trails all the way to the Southern Uplands in Scotland.

Denham Deep Lock is the deepest on the Grand Union, shifting boats up by almost 3.5 m so the canal can reach an aqueduct over the Frays River just before it joins the Colne. Fran’s Tea Garden by the lock cottage is a popular local destination, while the woodlands on the other side of the canal form part of an extensive Local Nature Reserve (LNR) including two Sites of Special Scientific Interest. The next bridge along is known as Turnover Bridge, a generic term for any bridge where the towpath changes sides, although in this case it marks the end of a stretch with paths on both sides of the waterway.

The Loop crosses the bridge on a third diversion away from the towpath, continuing north for a while parallel to the canal just within Denham Quarry, now converted to five Hillingdon council-owned fishing lakes also popular with overwintering birds, and part of the LNR.

Chiltern Main Line viaduct at Denham Quarry, soon to be joined by a rather large example carrying HS2.

A tall viaduct takes the Loop under the Chiltern Main Line, opened as the Great Western and Great Central Joint Railway (GW&GCJR) in 1906 as part of a route from Marylebone and Paddington to Birmingham and the north of England, in competition with the London and North Western Railway’s line from Euston. Across the next lake to your right past the viaduct is the Hillingdon Outdoor Activity Centre: this evolved from a sailing base opened in 1950 on one of the earlier flooded gravel pits in the valley and is now an educational charity.

The 1906 viaduct is now accepted as complementing the landscape, but plans to construct a modern successor of the London to Birmingham rail routes across the valley have met vociferous local opposition including from the Colne Valley Park. High Speed 2 (HS2), the proposed high speed rail line from Euston, is currently planned to cross the area on a new 3.4 km viaduct. This will cross the Loop on a northwest-southeast axis just about where the trail turns away from the canal past the corner of the next lake. It’s likely there will be disruption to the route and possible diversions during construction, which could begin in mid-2018. The Activity Centre is due to be moved across the Buckinghamshire boundary.

More colourful narrowboats are visible through the fence on the left, moored up at Harefield Marina. Like the activity centre, this opened in the early 1950s but fell into neglect in the next decade, and was revived and reopened in 1985. A little further on, the Loop winds north again, running through rough woodland and along old quarry tracks, passing a curious earth-filled boat hull colonised with trees, to arrive in South Harefield.

Harefield

The view from Coppermill Bridge, Harefield West, looking north along the Grand Union Canal, with former mill buildings and modern flats under construction right.

Harefield is a sprawling ancient parish occupying the extreme northwest corner of London (and, formerly, the extreme northwest corner of Middlesex). It’s centred on a large village green by a crossroads on a raised plateau above the Colne to the east, though its parish church is about a kilometre south, further down the hill. It’s another Anglo-Saxon name, meaning military field, and is mentioned in Domesday as a relatively large village. Its most famous feature is arguably Harefield Hospital, a specialist heart and lung hospital established in 1937, where the first heart and lung transplant in the UK was performed in 1983.

This area’s relative remoteness from railway lines restricted development and today, aside from the clusters around the village itself, South Harefield and Harefield West where this section ends, it’s one of the most rural parts of the Hillingdon. Ironically, you don’t really see this from the Loop, which runs either along the canal or through built-up streets, but if you catch the bus back to Uxbridge, you’ll find it’s a surprisingly long trip on country roads through open fields.

Black Jack's Mill: note the mill race still running beneath the building.

The trail rejoins the canal at Widewater Bridge, by Widewater Lock, the first of three locks providing picturesque settings along the last stretch of today’s walk. The brick and slate lock cottage, built around 1800, is now Grade II listed.

Further along is Black Jack’s Lock, with its adjacent part-17th century timber-framed mill house and cottage above a branch of the Colne, also Grade II listed. You can still see the mill race running beneath. In recent years the building has housed a restaurant and an upmarket bed and breakfast but last time I passed it was up for sale.

To the left of the canal here are more lakes forming part of the Mid-Colne Valley Site of Special Scientific Interest mainly because of their bird life. One of the largest expanses of water in the regional park, Broadwater Lake, between Widewater and Black Jack’s locks, is operated partly as a fishing lake, partly as a nature reserve managed by the Herts and Middlesex Wildlife Trust. Further on, approaching Harefield West, the canalside becomes built-up again, with aforesaid luxury dwellings on the right, Behind these, a triangle of chalk grassland, unusual at this distance from the Chilterns, rises up to the plateau. Known as Coppermill Meadow or Mount Pleasant, it’s also part of the SSSI.

The London Loop’s final dalliance with the Grand Union Canal and the river Colne ends just before Coppermill Bridge, next to the large and handsome Coy Carp pub, originally built to service the canal and formerly known as The Fisheries. Long distance walkers could follow in the hoofprints of the old tow horses along the Grand Union Canal Walk from here all the way to Gas Street Basin in Birmingham. The towpath also provides a link to the London Countryway at Kings Langley.

It’s worth walking on for a few steps under the bridge and surveying the scene at Coppermill Lock, with the Colne to the left, and a broad basin and weir serving the former mills to the right. A corn mill stood on this site at least since the early 1600s, which was either supplemented by or became a paper mill in the late 17th century. It operated as a copper mill from 1803-1870, then again as a paper mill and, from 1890, an asbestos works. By the 1950s several rubber companies were based here. Today the site is in the final stages of conversion to an upmarket residential area known as Royal Quay.

Take care as you cross the narrow bridge and the winding lane beyond it, with one-way traffic controlled by lights. Where the road widens, you walk past the former mill owner’s house on the left, a fine Grade II listed classically-styled two storey Georgian brick building that was later used as the rubber company offices and is now being turned into flats. The Hillingdon Trail, introduced in the next section, briefly rejoins here. The section ends a few paces further on, before the Loop starts to climb from the valley along Summerhouse Drive, towards the rolling fields of Hertfordshire.

Harefield West bus island with London Loop board visible just left of centre, and the Buckinghamshire side of the Colne Valley rising above the hedge on the left.

This is one of the few Loop sections without a rail connection – instead there’s a bus island nearby. Until recently there were no Sunday buses so Loop descriptions also describe a shortish link onwards to Harefield village centre, which is worth a look if you have the time, and offers a wider range of food, drink and other services.

• Download full route description (PDF)
• View Google map
• Official Transport for London pages:
  Hayes and Harlington to Uxbridge
  Uxbridge to Harefield West