Steven Norris readily admits that he's better at talking than walking and doesn't get out in the fresh air often enough: "What do they say? A bad ride is better than a good walk." But once a year. he turns out in his trainers, £11 miles of pavement, and is surprised how much he enjoys it. The event is an annual charity walk across the bridges of London, which he first did when he was a Department of Transport minister with responsibility for the capital between 1992 and 1996. He's done it ever since, and now he's Conservative candidate for Mayor of London, it makes good political sense to keep on going.
Starting in the City, at the north end of Tower Bridge, and finishing in the park at the south side of Battersea Bridge, the route folows London's main artery to cross its historic heart and 11 of its bridges. There are riverside promendades, famous buildings, changing skylines and the odd murky corner.
"What's good about it is that you see the city from its best vantage point, which is the river," says Norris. "And you start with that extraordinary explosion of new architecture and geometry on the north bank between Tower Bridge and Waterloo. Then you come to the metro politan West End between Waterloo and Westminster and, after that, it becomes more residential, quieter and calmer as you go down to Battersea. The river itself changes from high to low, and there's the sheer pleasure of seeing so many different places.
"Even someone as unfit as I am can do it without feeling that it's a massive burden. And it's not a competition - I walk with a group of friends from the department, and my son Edward, who's now 14, has come with me a couple of years."
Norris's ideal lunch spot would be the Oxo brasserie, with its wonderful view of the city between Blackfriars and Waterloo, or Ransome's Dock, tucked beside a small wharf in Battersea.
Up to 70 people do the walk on charity day, and they pause to eat sandwiches and an orange at the south end of Lambeth Bridge. This is one of the river's best spots for viewing the Houses of Parliament, where Norris was Member for Epping Forest until the last election.
The highlight of the walk for him, though, is not Westminster but Waterloo Bridge, the place he always takes visitors to show them what London really means. "You look east, and there's that great panorama of St Paul's and the City and Canary Wharf in the distance - unique, nothing else like it in the world. And to the west, the Palace of Westminster, Terry Farrell's Charing Cross station, the whole metropolitan area. It's a view that sums up the best of London. It's majestic, what Wordsworth called 'that mighty heart'."
You only need three hours to test out the rest of Words-worth's 1802 sonnet Composed on Westminster Bridge, including the first line: "Earth has not anything to show more fair." But if you want to do it for charity, the next organised walk is in November: date available soon from Imperial Cancer Research Fund on 020-8390 9575.
Legs 11... crossing those bridges
1 Tower Bridge (built 1894): a bus driver once had to jump the gap as the bridge opened under him. The 1,000-ton bascules have been up and down more often than - well, supply your own Norris joke.
2 London Bridge (1972): heads displayed on its medieval predecessor included those of William Wallace, Jack Cade, Thomas More and Bishop Fisher. They were parboiled in the gatehouse, then dipped in tar to preserve them.
3 Southwark Bridge (1921): Its Victorian forebear was a footbridge of three magnificent cast-iron arches, which bankrupted the Rotherham foundry that made them.
4 Blackfriars Bridge (1869): London's widest, at 105ft, it has pulpit-shaped pier heads to match its name, derived from the former Dominican monastery on the north bank.
5 Waterloo Bridge (1942): the longest at 1,250ft, and the first made with reinforced concrete beams. Wooden pilings from its predecessor were so well preserved they were pulled out of the clay and used to veneer new coaches for the London, Midland and Scottish Railway Company.
6 Westminster Bridge (1862): the oldest still in use. Its dominant colour of green matches the leather benches in the House of Commons.
7 Lambeth Bridge (1932): mainly red to match the benches of the nearby House of Lords.
8 Vauxhall Bridge (1906): the first to carry trams. The piers bear bronze statues of women holding symbols of the arts and sciences.
9 Chelsea Bridge (1937): A modern suspension bridge: the falling tide was ingeniously used to lower the central sections into position from barges.
10 Albert Bridge (1873): the only one of this group of bridges never to be replaced.
11 Battersea (1890): Flumini Vincula Posuit (he chained the river), says the monument on Victoria Embankment to Sir Joseph Bazalgette, who built London's main sewers and designed this bridge.
The practicals
Underground to Tower Hill to start the walk. From Battersea Bridge catch bus south to Clapham Junction rail station or north to South Kensingtom underground. Take an A-Z or large scale map. Bridge by Bridge through London by Tony Waters (80 pages, Pryor Publications, £4.99) gives details and sketches of all bridges to Teddington Lock. Tourist Board (020 7932 2000) supplies a free information pack on accomodation and guided walks.
