The 4x4 is often spotted on London's roads

About 16% of London motorists plan to buy an off-road vehicle in the next year, twice as many as Scottish drivers who face tougher terrain and weather.

The AA, which conducted the survey of 2,000 drivers, said it seemed strange that Londoners chose cars which were "impractical" for city life.

Mayor Ken Livingstone has branded 4x4 drivers "idiots" and has said he would like them banned from the school run.

'Chelsea tractors'

"When you see someone trying to manoeuvre it round the school gates, you have to think, you are a complete idiot," he said in a GMTV interview.

The vehicles have been dubbed "Chelsea tractors" because of their popularity in certain quarters of London, with supporters citing their safety and space for carrying children and animals.

But Lloyd East, general manager of AA Financial Services, said: "When you consider the volume of traffic in London it is almost counter-intuitive that drivers in the capital opt for large vehicles traditionally associated with rougher terrain.

"Perhaps it's just the dream of cruising in open country and along rough tracks, dreams unlikely to ever be fulfilled, that drives Londoners to go for cars that are impractical for life in the city?"

The survey found that the over-50s were keenest on large off-road vehicles.