Much of the UK's annual billion pound bill for whiplash injuries could be avoided by drivers correctly positioning their head restraints, finds Thatcham, the Motor Insurance Repair and Research Centre.

It monitored 4,000 motorists in traffic to see how many had their head restraints correctly adjusted – only one in five did.

This could mean that up to 80% of Britain's 25 million motorists and their passengers are now risking neck injuries as a result of incorrectly positioned head restraints.

An estimated 250,000 people suffer from whiplash and back-related injuries each year, costing more than £1bn.

The Association of British Insurers (ABI) says that between a third and a half of injuries could be prevented by correctly positioned head restraints.

Women are more vulnerable than men – they are twice as likely to suffer injury as they have to sit further forward when driving.

ABI's Motor Manager Penny Coombs, says: "The Government's recent road safety strategy understandably focuses on serious injuries.

"But in terms of numbers affected, whiplash is the source of far more pain and suffering for motorists.

"This is a major and a growing problem, not just in the UK but throughout the world.

"These injuries are increasing as the growth in traffic leads to more rear-end collisions, which are three times more likely to cause whiplash."

Whiplash occurs when a head restraint is set too low towards the neck and the head is forced backwards and then whipped forwards, compressing and stretching the vertebrae.