Walk London CAPITAL RING[section 7] Richmond Bridge to Osterley Lock (4½ miles)
After the very-green section 6 comes a very-blue 7. The first half's along the Thames, the second's along the Grand Union Canal. It's another winner.
Time to leave the pubs and shops and boatyards of Richmond behind. The towpath heads north, a bit parched at the moment, but there's plenty of water in the Thames alongside. There are a couple of bridges to duck under, the first (Richmond Railway Bridge) for trains, the second (Twickenham Bridge) for an arterial road. And then, as the Old Deer Park spreads out to the right, a mysterious line crosses the path [photo]. If this were Greenwich you'd know precisely was it was, but that's fifteen miles east so how could it be? Ah but it sort-of is, it's the Kew Meridian, which was the line of longitude preferred by King George III. He built an observatory in the park (it's still there), specifically to observe the Transit of Venus in June 1769. There are also three obelisky meridian markers, one very close to the Thames if you fancy nipping into the neighbouring recreation ground for a look.
That's South London finished with. Here's where the Ring crosses to the north bank of the Thames, which hasn't been in sight since the very beginning of the walk three dozen miles back. It's a memorable crossing too, up and over Richmond Lock which is a magnificent Victorian structure built to maintain river flow upstream [photo]. At high tide the sluice gates are opened and boats can sail through unimpeded, but at other times they have to use the lock (charge £5). Pedestrians get to walk along the top, between the globe lamps and swirly metalwork, with a chance to scrutinise the machinery or peer down at passing river traffic [photo]. You may also be distracted by the roar of aeroplanes flying low overhead. The next bend north is directly underneath the Heathrow flightpath, so a steady succession of Jumbos and Airbuses shatter the calm every 90 seconds or so.
A detour inland is required to negotiate the mouth of the River Crane, which is a shame because walking round Isleworth isn't quite as pleasant as walking by the water. But Old Isleworth is picturesque, ably assisted by its Thamesside location and what looks like an old church on the riverbank. On closer inspection, however, the tower is the only part of All Saints to have survived an arson attempt in 1943, and the rest is a strikingly modern rebuild. And that's not really the river either, it's a semi-drained channel round the back of Isleworth Ait (one of the Thames's longest islands) [photo]. When the tide's low it's possible to walk out on the mud and across a ramp of stepping stones to reach the tied-up boats and nature reserve on the other side [photo]. Possible, but perhaps not advised. Safer to take a seat on the terrace at the London Apprentice pub, so named because wannabe City tradesmen used to sail here to celebrate the end of their apprenticeships. A long way from the City, but a fine place to celebrate.
One last glimpse of the Thames, then the Ring turns unashamedly into Syon Park. I must admit I was expecting prettier, but the offical route hugs a wall between the public park and the private gardens so never quite feels special. There's one point where the vista opens out across the front lawn to reveal the facade of Syon House - a bit like a rather bland castle [photo]. But then it's swiftly back to an extensive car park, and lots of metal railings, and a very big garden centre. The Duke of Northumberland opened Britain's first horticultural supermarket here in 1968, and just one Spring Sunday's takings must provide a tidy sum towards the upkeep of the estate.
Here's the edge of Brentford, but more importantly here's the Grand Union Canal. The Capital Ring will be following that for a fair few miles (though not all 93 to Braunston), joining the waterway at seriously-modernised Brentford Lock. Don't think ramshackle gates, think spruced-up canal basin surrounded by shiny apartments and cosmopolitan dining opportunities [photo]. But this imported affluence doesn't last long. The towpath suddenly snakes through a large gloomywarehouse, whose girders and corrugated iron walls creak and rattle menacingly when the wind's up [photo]. I can't imagine why this ramshackle structure has somehow been allowed to survive here, but I fear it won't be long before it becomes "high quality public realm".
The next building's in complete contrast - the global headquarters of pharmaceutical giants GlaxoSmithKline. Employees work in and around a 16-storey curved glass tower block, with a small waterfall and a weird sculpture plonked outside by the canal for good measure. The towpath passes beneath the Great West Road - the interesting stretch with all the Art Deco offices, but we're not going there. Instead there's all the twists and turns of an urban canal, which means trees and bushes shielding a succession of industrial units, railway lines and secluded meadows. At one point, by a weir blessed with swans, the M4 scythes shamelessly past atop a low viaduct on concrete stilts. It's not as ugly a stretch as you're thinking, at least not in leafy spring. But the next wiggles of canal will have to wait for section 8 - Osterley Lock's as far as this walk goes.
(and a reminder that Walk London's Spring into Summer Weekend starts tomorrow, with more than 50 free guided walks taking place across the capital. Most are wussy walks around the touristy centre of town, but there are also some more challenging treks further out. Highly recommended... for those who can be bothered to plough through 58 separate pages on the website, sigh)