"Although passengers in a 4x4 are less likely to suffer harm in an accident than those in a smaller vehicle, their owners are increasing the risk of injury to themselves and others by their failure to observe common safety measures, according to research from Imperial College, London, which is published in the British Medical Journal.

"The pattern is an example of "risk compensation", where the safer a person feels the riskier the behaviour they indulge in.

"A record 187,000 4x4s were sold in Britain last year, double the number a decade ago. One in seven cars on the road is now a 4x4, according to the Department of Transport....

"Last October the BMJ published an American study showing that 4x4s were more dangerous to pedestrians than normal cars. Tests showed that people who were hit by the vehicles in accidents were four times more likely to die than those hit by other cars.

"Previous studies have shown that drivers using mobile phones have four times the risk of an accident. On that basis, 4x4 drivers are at 16 times the risk of having an accident, given that they are four times more likely to use a mobile compared with other drivers."