Doctors are calling for all riders of road-legal quad bikes to wear helmets in a bid to cut the number of road accident injuries caused by collisions involving the vehicles.

Health professionals are saying that lives are being put at risk as the wearing of helmets is not compulsory despite the bikes reaching speeds of 90mph.

The warning comes as the sales of the bikes are increasing. Suppliers have said that from selling a few hundred each year, they have been selling thousands for the past five years.

Both comedian Rick Mayall and rock musician Ozzy Osbourne suffered serious injuries when falling off their quad bikes.  Mayall spent five days in a coma following his quad bike accident while Osbourne spent eight days in a coma, broke eight ribs and punctured a lung.

The road safety minister Mike Penning said that the government was not planning to make the wearing of helmets compulsory but that the matter was under review and it did encourage riders to wear a helmet.