AT THE Elephant and Castle roundabout in south London, more than a dozen cyclists wait at a red light. Some, wearing lycra and bright backpacks, hunch over their expensive-looking cycles and push to the front. Others, in suits, sit astride bulkier commuter bikes. They are all men. Before the light changes, the lycra-clad ones rush forward, while the others weave cautiously between the many taxis and white vans.

After decades of decline, cycling is booming. According to the Department for Transport, people cycled farther in 2010 than in any year since 1991. In London some 540,000 trips a day are made by bicycle—twice as many as in 2000.

Public transport is dearer and more crowded than it was, and household incomes more pinched. And Sir Chris Hoy, who took three gold medals in cycling at the Beijing Olympics, has raised cycling's profile. (That the velodrome is among the most impressive of the new Olympic venues in London is testament to the effect.)

Public investment has helped too. Boris Johnson, London's mayor and a keen cyclist, has laid on jazzed-up “cycle superhighways” that criss-cross popular commutes. His most visible imprint on the city so far is a cycle-hire scheme, which has expanded eastwards. By 2026 Mr Johnson wants cycling to have quintupled from 2001 levels.

To get there, though, cyclists will have to start looking less like Mr Johnson. Despite its working-class origins—one of Britain's first cycling outfits was the socialist Clarion Club in Birmingham—two-wheeled transport is now mostly the preserve of wealthy men. The Evans Cycle shop in Canary Wharf sells custom racing bikes for as much as £10,000 ($15,500) to cycle-mad bankers. In hipper Shoreditch, small independent stores hawk colourful, one-gear bikes to graphic artists and web designers.

Nationally, the richest 20% of people cycle an average of 33 miles a year to work, compared with just nine miles for the poorest 20%. Two-thirds of those using Mr Johnson's cycle-hire scheme claim household incomes of more than £50,000 a year, though only a quarter of London residents make that much. And 77% of them are men. In Amsterdam, by contrast, most cyclists are women.

The main roadblock is safety: overall, 62% of people think it is too dangerous to cycle, and around 75% of women do. Accident rates have been falling in London, but 16 people died cycling last year. Cyclists insist that junctions like Elephant and Castle are life-threatening, especially when filled with heavy lorries, which account for many cycling deaths. Ghost bikes—painted frames left as memorials to fallen cyclists—are an increasingly frequent sight.

In other cities, such as Bristol, cycling has been encouraged by lower speed limits for cars on popular roads and traffic-free routes to bypass dangerous junctions. But Boris Johnson has proved reluctant to go as far, partly for fear of slowing down London's already sluggish traffic. Asked recently about a proposal to redesign the giant Elephant and Castle roundabout, the mayor responded that “if you keep your wits about you”, the intersection is “perfectly negotiable”.