Ref. 29157-5One in three motorists may be breaking the law by driving vehicles with dirty number plates.

Following the recent wintry weather, the RAC has warned motorists to clean up their act or face possible prosecution and a fine of up to £1,000.

And Swindon motorists have no excuse, with professional car washes costing little more than £3.

James Molloy, RAC Head of Accident Care, said: "As speed cameras increasingly become a sight on UK roads, police forces are using regulations which state both front and back registration plates must be clearly visible to ensure number plates can be read by the cameras."

In a survey of motorists 62 per cent were unaware of this law.

But it is not only for the sake of speed cameras that vehicles should be kept clean, according to Mr Molloy.

Dirty headlights and windows can impair visibility a contributing factor to the higher rate of accidents at this time of year.

"It's important you have clear visibility of other vehicles on the road and that they can see you," he said.

"Before you set off on your journey, don't just de-ice your front windscreen.

"Check your lights, including your fog lights, and your side mirrors are clear and top up your washer bottle so you can maintain a clear windscreen when on your journey."

Drivers wanting to take extra special care keeping their cars clean could always choose a professional car wash.

The Ocean Car Cleaning Centre, in the North Orbital Shopping Centre in Thamesdown Drive, offers customers a range of washes.

The basic "bog standard" four-minute wash, at £3.25, involves manually "prepping" the front and rear of the car with a brush and soap, before sending it through the conveyor belt for a wash, rinse and dry.

At the top end of the scale, drivers may opt for a full 45-minute £20 valet service, including prepping, triple foam application, polish, wax, tyre wash, special chemical rinse for alloy wheels, an under-chassis wash to remove road salts, plus an interior vacuum.

What all the washes have in common, according to Ocean manager Trevor Rose, is a careful, manual number plate clean.

"No two cars are the same size so rather than using mechanical brushes and risking breaking the plates we do it by hand to make sure all the dirt is cleaned off," he said.

Ocean cleaned 1,000 cars last week, and Mr Rose said this was the busiest time of the year because of the state of the roads and poor weather.

Andy Tate