More than one million drivers aged over 65 refuse to admit they are a danger behind the wheel, a survey has revealed.

The motorists risk a £1,000 fine and prosecution for failing to disclose serious medical conditions that would legally prohibit them from driving.

Almost three in ten older drivers have medical issues that must be disclosed to the Driver and Vehicle Licensing Agency (DVLA), such as visual impairments, diabetes, heart conditions and epilepsy.

But just 49 per cent of these drivers have told the DVLA about their conditions, according to the survey for Direct Line. Most drivers say they do not believe their condition will affect their driving. 

According to the road safety charity Brake, poor eyesight is thought to be the biggest health-related cause of crashes, with 2,900 casualties a year.

UK drivers aged over 70 must fill in a self-assessment form every three years to renew their licences. But critics say the form should be accompanied by a mandatory medical or driving test. Relatives of people killed by elderly drivers have backed calls from Brake for motorists over 65 to pass an eye test when they reapply for a licence.

But poor vision is not exclusive to those over a certain age and regular eye tests should be as important as regular car servicing and maintenance to all drivers. Recent AA figures show that the average yearly labour and parts cost of running a car is £434, surely your eyes and vision is worth more than that.