The Grand Union Canal, a serene sanctuary amid the urban sprawl

It was a Saturday afternoon in September, the end of summer, and I was feeling sorry for myself. I’d gone to see my son play football in Slough. He was on the bench, his team had lost, and now I had to carry his kitbag home while he went out with his teammates. I’d missed my bus back to Uxbridge and it was an hour until the next one. I was trudging back into town when I saw a signpost for the Grand Union Canal. Along the towpath, I reckoned it was about eight miles to Uxbridge. Sod it: I decided to walk home.

When I finally reached Uxbridge dusk was falling and I was feeling happier than I’d felt in ages. I’d hardly seen a soul (a lone fisherman drinking beer, two blokes dredging for scrap metal) but I’d seen swans, herons, cormorants and my first kingfisher. That’s the great thing about the Grand Union Canal: an industrial relic of a bygone age, it really ought to be an eyesore. Instead, it has become a sanctuary amid the urban sprawl.

The Grand Union Canal runs for 137 miles, from London to Birmingham. I’d love to tell you I’ve walked all of it but I haven’t, not nearly. However, the bits I have walked so far are among my favourite walks in Britain: from Brentford to Hanwell, from Watford to Rickmansworth, and, best of all, through the bustling heart of Birmingham.

Brentford? Watford? Birmingham? Is he taking the piss? Not at all. It’s easy to find bucolic walks that run through unspoilt rural scenery. What’s so good about the Grand Union are the stretches flora and fauna have reclaimed. The Slough arm was built to carry bricks. Now it’s a haven for wildlife. Boats on the Paddington arm used to carry coal. Now they carry daytrippers. Waterways designed for commerce have become nature corridors. The hard-nosed businessmen who built them would be amazed to see how they’ve changed, from places of hard graft to places of idle leisure.

Nowhere sums up this transformation better than Birmingham, where the canal reaches its triumphant terminus. Here, it has become a lively boulevard, lined with trendy bars and restaurants, a handy short cut from the station to the symphony hall. Last time I was there I met some artists who’d turned a narrowboat into a floating gallery, and travelled all the way to London along the canal. It took them six weeks. It sounds fantastic. Slow travel is the future. Who needs HS2?

Canal walking is the best sort of walking for lazy layabouts like me. The towpaths are flat and straight and well signposted, with a pub every few miles along the way. I’ve never lived on a canal boat but I know a lot of folk who have, and it’s a fascinating subculture — part-hippy, part-gypsy, as close as you can get to a nomadic lifestyle in Britain nowadays.

It’s a Saturday morning in October, autumn’s begun, and I’m back on the canal, walking along one of the bits I know best, from Harefield to Rickmansworth Aquadrome. In the porthole of a narrowboat I see a sign that says: ‘Beatings will continue until morale improves.’ I don’t know what it means. I don’t know who put it there. But for some reason I find it unfathomably funny. That’s the thing about the Grand Union Canal, what makes it so special. It shows you don’t have to travel far to end up a world away.