A PANTO horse's head, a paddling pool, half a million pounds stashed in a suitcase and even an 8ft blow up spaceman were among items flung out of cars onto the motorway in recent months.

Now motorists who dump litter at the side of the road have been warned they face £50 on-the-spot fines.

A campaign launched yesterday by the High-ways Agency and Keep Britain Tidy is urging lazy drivers to take their litter home.

A survey of the country's filthiest slip roads found some of the worst were in Wiltshire.

Keep Britain Tidy rated the outward slip road from the Leigh Delamere service station on the way to the M4 as "downright dirty."

And the roads at Membury service station, near Newbury, was given a similarly abysmal score.

Heather Ransom, who surveyed the Swindon area earlier this month, said: "Most of the litter was from food bought in service stations, such as coffee cups and crisp packets.

"Many of the slip roads near Swindon were dirty but the roads leaving services were particularly bad."

The Highways Agency attempts to keep the main roads clean using a special verge vacuum a powerful suction device attached to the back of a lorry.

The vacuum passes along the M4 in the Swindon area once every two or three weeks.

Every six months the equivalent of a quarter of a million rubbish bags full of litter are collected from the verges of motorways and trunk roads in England.

Most of the rubbish removed from the motorway consists of food litter and plastic bags.

But beds, washing machines, passports, disco lights, a circus sign, stepladders, pushbikes and lawn mowers have also been found.

"Rubbish on the motorway is not only unsightly it can be dangerous and is costly to remove," said Chris Hope, Highways Agency Traffic Operations manager.

"The money that is spent on cleaning litter from the verges is money that could be used to improve our roads, rather than pick up the rubbish of irresponsible motorists."

More than 90 per cent of people surveyed across the South West said they hated seeing people throwing litter out of their car window.

Keep Britain Tidy discovered litter was the region's biggest driving bugbear more irritating than middle lane drivers, dirtier than spitting out of the window and even more repulsive than watching people pick their noses.

Amanda Booth, regional director of Keep Britain Tidy, said: "With millions of tourists visiting the region every year and many expected this Bank Holiday weekend, we really must stop and think about what kind of impression these people get when they see our road sides swallowed by litter.

"The thoughtless habit of these motorists is a blight to our towns, cities and countryside.

"We must hold up a stop sign to car litter."

The new campaign will feature posters and stickers asking road users to take pride in the environment, along with a radio ad campaign voiced by TV's Angus Deayton.