ILLICIT drug-taking has increased four-fold in 10 years, according to road accident figures published yesterday.

The survey also showed that a quarter of car drivers killed in accidents were found to have traces of medicinal or illicit drugs in their bodies.

The latest figures show that, since a similar survey 10 years ago:-

q Illicit drug-taking has increased four-fold.

q An increasing number had taken more than one kind of illicit drug.

q The presence of medicinal drugs was more or less the same.

q The presence of alcohol had fallen substantially.

Drivers could soon face roadside drugs tests with the development of a roadside screening device.

The provisional figures from the first seven months of a three-year Transport Department study revealed that, in tests on 301 road accident fatalities, more tested positive for drugs than for alcohol.

The survey involves taking blood or urine samples from those killed in road accidents in Scotland, England and Wales, and includes drivers, riders , passengers, and pedestrians.

The Royal Society for the Prevention of Accidents said the figures were ''disturbing but not surprising'' and showed the need for some type of action to combat the problem.

''Roadside testing is already carried out in the USA and, if it was tried here, even on experimental basis, it would help to build an even more accurate picture of the situation,'' said RoSPA's road safety adviser Dave Rogers.

He went on: ''Drugs impair ability when driving and something needs to be done about them. It is not just a question of illegal drug use, as some drugs purchased from a chemist after being prescribed by a doctor could also have a dangerous effect on a person's ability to drive.

The RAC said the study confirmed its concerns that the law covering drug-driving had to be clarified to allow ''effective roadside enforcement''.

The findings showed that the soft drug cannabis was the main drug detected and there were no cases involving cocaine or LSD and ''very little evidence'' of ecstasy.

But Roads Minister Bar-oness Hayman said: ''These figures are worrying and show raised levels of drug use among passengers killed as well as drivers.''

She said the Home Office police scientific development branch was working on a possible drugs roadside screening device and was due to report its conclusions next spring.

The Government is also discussing with police forces how best to enhance officers' ability to detect drug use by motorists.

The preliminary results related to 301 deaths since October 1996. Of those that tested positive, 66 were over the legal alcohol limit, but 69 were found to have taken drugs, of which more than 50 were illicit drugs.

Of these drugs, cannabis made up the greatest number, with 30 cases. The survey also showed that a quarter of car drivers killed in road accidents had traces of medicinal or illicit drugs. The statistics also showed that the age profile of those killed who took illicit drugs was between 20-30 years.

The Association of Chief Police Officers said it was concerned at what this early data had revealed and added: ''These early indicators show that the police service will need to increase its vigilance and look more actively for signs of use of drugs and not just alcohol when dealing with drivers.''

The survey is being undertaken by the Transport Research Laboratory and the Forensic Science Service in liaison with coroners and pathologists across Britain.

The figures relate only to drivers and passengers killed in road traffic accidents and do not include any roadside tests of motorists.

Current legislation makes it clear that motorists must not drive while under the influence of drink or drugs, but there is not a defined safety limit for drug use that for alcohol. The onus is on to the police to prove, not only that drugs are present, but also to prove impairment.