Well-off motorists tend to drive around in dirtier cars, according to an AA/Populus survey.

Only 6% of car owners from professional and managerial backgrounds wash their vehicle once a week, compared with 8.5% for lower-income owners.

The gap widens among those who clean their car twice a week, with 16% of lower-income owners washing their vehicle fortnightly, but only 11.5% of wealthier owners doing so.

A total of 3% of the 18,080 AA members surveyed washed their car once a year or not at all. Among women drivers, this figure doubled to 6%.

According to the survey, drivers in Scotland and north-east England have the cleanest cars, with 11% of owners in these places washing their cars every week compared with 4% in London and in south-west England.

The survey found that 47% wash their cars every couple of months or every six months.

Across the age bands half as many younger drivers (22%) than those aged over 55 (44%) washed their car once a fortnight or weekly.

AA president Edmund King said: "Many drivers do take pride in their cars and their Sunday morning car wash has become a ritual.

"Keeping your car clean, particularly windows, lights and number-plates, can keep you on the right side of the law."