Thomas Heatherwick: 'Design is like solving a crime He strives to avoid a signature Heatherwick "look": "Life would be a lot less interesting if we were plagiarising ourselves," he says. Yet much of his work is stamped with flamboyance, freewheeling form, and an impish desire to upend conventional thinking. The pedestrian bridge he designed for Paddington Basin in west London in 2002 is a case in point: unlike other opening bridges, which, he says, "flap up like pinball flippers," Heatherwick's Rolling Bridge curls back upon itself until it forms a neat circle on one bank. It is effective, unexpected - and beautiful. The UK pavilion he built for the 2010 World Expo in Shanghai is another good example. Having decided to create a "cathedral" to showcase the Millennium Seed Bank collection at Kew Gardens, Heatherwick constructed a plywood box 15m wide and 10m high. He then cast a quarter of a million seeds in the tips of 60,000 7.5m-long acrylic rods, which protruded from the box in every direction like a thick halo of silvery, swaying hairs. Visited by more than eight million people over six months, the magical result won the Expo's prize for best pavilion. "People have the impression that it was a kind of artistic, eccentric expression," Heatherwick says. Yet I can tell you rationally every reason why the UK pavilion was exactly like it was. This summer, Heatherwick will be in the public eye for reasons besides the new book and the exhibition at the V&A. His design for a cauldron for the Olympic flame will be revealed in July. He has also redesigned London's double-decker bus: three of eight prototypes are on the streets already. "It's 50 years since the Routemaster was launched," he says, "and the world has changed. The red double-decker bus is a key part of the architecture of London, yet recently we've thought of buses as something you procure from a catalogue. He launches into a litany of what went wrong with their design, from the colour of the handrails - a "nuclear-warning yellow" - to the lighting. "Fluorescent tube lighting is what you have in a battery chicken farm," he says. Human flesh tissue is not flattered 30cm away from a fluorescent tube. So you had an environment that was as jarring aesthetically for the dignity of the passenger as it was possible to be. We have low-energy individual downlights. Heatherwick also created spiralling windows that follow the two staircases leading to the upper deck at either end of the vehicle. "Often you go up a staircase in a bus, and you enter a plastic tube," he says. But why not give someone the best view of London? It feels grand to sit on the top floor of a double-decker - it gets you in the stomach. Our role was about not treating humans as rats that need to be transported from one place to another, but about trying to re-establish the dignity of bus travel. We were also working to make a bus that would use 40 per cent less energy. As he speaks, Heatherwick appears inspired - fired by the nitty-gritty of the project under discussion. These days, his studio usually has around 15 projects on the go, and this year's predicted turnover is £6.5 million. Does working on so many diverse commissions ever frustrate him? "Clearly I've got an ego," he says. But I couldn't retreat to making pieces that sit in people's private collections - that holds little interest. For me, the hardest thing is doing things in the public realm. My dream commission would be to design a hospital, because hospitals are some of the worst environments I have ever been into. There are already people making amazing art galleries. For me, culture is everywhere around you: it's in the public toilets, it's in the infrastructure - it's the health service, the schools. At the root of everything I do is a fascination with ideas - what ideas are for, what jobs they do. An interest in ideas is a sign of human life. People are fascinated by what the future is going to be - and the future is going to be an accumulation of ideas. Heatherwick Studio: Designing the Extraordinary" is at the V&A (020 7942 2000) from May 31. Thomas Heatherwick: Making" (Thames & Hudson, £38) is published on May 28. Heatherwick will be at the Hay Festival (hayfestival.com) on June 5