Ominously coinciding with the anniversary of JF Gravelet Blondin's death - the most famous wirewalker of all time - circus performers Didier Pasquette and Jade Kindar-Martin (left) will step out tomorrow for a record-breaking stunt, a hair-raising stroll across a 1,000ft-long, 1in- thick wire, running 150ft above the Thames between Bernie Spain Gardens, by London's Oxo Tower, and Victoria Embankment. The walk launches the Thames Festival, an event dedicated to raising the profile of the capital's swampy waterways.

The two daredevils will walk from opposite ends of the wire and meet in the middle, where they will elegantly step over one another to continue their precarious journey. The first attempt to cross the Thames on a high- wire was in 1861, when Madame Genevieve, hailed as the female Blondin, lost her nerve halfway and had to climb down one of the supporting structures to safety.

Despite this precedent Didier and Jade remain confident, but are careful to point out the difficulties presented by water. "The movement of the water can make it look as though the wire is moving, adding a certain amount of spice to the proceedings," explains Jade with a certain amount of bravado. "When I think of the danger it all gets a bit hairy." Bernie Spain Gardens, London SE1, tomorrow from 7pm, free

Fiona Sturges