LONDON (REUTERS) - Behind a start line in a field in southern England, a group of drivers rev their engines, raring to open the throttle on noisy machines more used to cutting grass than racing across it.

For a few dedicated motor sport lovers, Sunday (May 1) marked the start of the British lawnmower racing season, in which participants drive laps around a track in slightly souped-up sit-down mowers with the blades removed.

The championship, dreamt up in a countryside pub in 1973, runs from May to October and features three categories: roller-driven mowers; wheel-driven mowers and wheel-driven lawn tractors.

"It's a little unusual, it's not like jumping in a car and turning the wheel and peddles and gears," said Mr Dean Fuller, British Champion on the wheel-driven variety, at the season's first meeting in Surrey.

"You have got to learn how you lean, how you brake, the different types of surfaces ... So it really does take three or four years before you get the hang of (it)."