'It's like being in Palermo,' ventured Russell, my partner, as he pushed open the window, welcoming in the roar of traffic below. Our room, fuggy with fumes, could use some fresh air. As we lay tipsy on the bed and the sirens wailed around us, I had to remember that we were actually spending the first night of our holiday in Stratford, not Sicily.

Can anywhere become interesting if the right mindset is applied? When I glimpsed a leaflet in a north London park giving details of London's 'Capital Ring,' walking route, I was curious. Inside, a map outlined the 78-mile circular route through Woolwich, Crystal Palace, Wimbledon, Richmond, Harrow-on-the-Hill, Stoke Newington, Highgate and Hackney Wick.

We formed a plan: to walk the Ring in a week, 12 miles a day, with each night's accommodation - a pre-booked jumble of B&Bs, chain hotels and opulent riverside palaces - as near as possible to the route; to begin and end in Highgate (geographically convenient); and to raise money for the charity Walk Once More (www.walkoncemore.org), set up by a friend with a spinal cord injury.

Rucksacks bulging, a week or so later we strode into the glare of the Saturday morning sun, relishing no airport hassles, no glum faces and, thrillingly, no half-hearted compulsion to extract historical interest from an unknown city. This adventure would, we decided grandly, give perspective to our lives in the great metropolis. (Sipping a pint in Balham, halfway round, we watched sharp-suited commuters, so upright and serious, with the fascination normally reserved for an indigenous people.)

And from the start in Highgate, the Ring, a well-signposted route that meanders through mostly green spaces, threw up immediate delights, despite the hum of traffic never being far away. Near the disused platform of the former Crouch End station, a giant sculpture leapt out of the wall. It was a 'spriggen', a local goblin rumoured to steal human babies.

Other little-known sights slid past: ragged Abney Park Cemetery in Stoke Newington, with its 300,000 graves and deep earthy smell; a flotilla of painted canal boats at Springfield Marina in the Lee Valley; kestrels hovering over Walthamstow Nature Reserve, the last surviving marshlands in London.

We soon learnt a few tricks: our first lunch, of smoked haddock kedgeree and chicken pie, was delicious, but that afternoon's walk was, groaned Russell, 'like being pregnant'. And too much booze was a no-no: a red-wine-fuelled first night in Stratford made the second stretch, down to Woolwich, initially rather bleak. But, as we strolled along the River Lee that Sunday morning, we became imaginers of other people's lives. Why was that man slumped on a bollard by the lock, head in hands? What lurked in those floating bin bags? Whose was the sodden black hoodie on the bank?