Almost half of parents would like black boxes measuring the speed, braking and driving habits of young drivers to become compulsory for motorists under 25, a study claims today.

Forty-six per cent of parents favour the mandatory installation of the GPS tracking devices, the insurance company Direct Line says.

A poll of 1,000 parents found that 75 per cent believed that the devices were an acceptable way of reducing the insurance premiums of their children, while 73 per cent thought it would reduce danger for inexperienced drivers.