Guy Martin famously often said, 'I love racing because it can kill you'. But he's a dad now, and he wants to see his daughter grow up to become a welder. The racing had to stop. But the thrill of an extreme, speed-based challenge still drives him, and his new mission is to hit a world-record-breaking 300mph on a motorbike he has built himself. Others have died trying. We also find him leaping out of a plane with a 1940s parachute, competing in a self-supported 750-mile bike-packing race through Arizona in 30 degree heat and channelling Steve McQueen in The Great Escape for a stunt jump over two barbed-wire fences. Speeding tractors (135mph) have replaced two wheels, and US truck racing is his new TT. All the above has been taken on with a dodgy ankle, which he keeps meaning to have replaced.