AN MP is calling for roadside drug tests and increased police patrols to deter young drunk and drugged drivers from getting behind the wheel.

Conservative former minister Chris Chope said: "More youngsters are taking the risk because the chances of them getting caught are so slim.

"The number of police officers dedicated to highways work has been reduced with cameras being used for detection. But cameras can't tell whether a driver had been drinking or has taken drugs."

The Christchurch MP's comments came after a new survey showed that one in five 17- to 18-year-olds had admitted drink driving while one in 14 had got behind the wheel after taking drugs.

The alarming figures were released as the number of young Dorset drivers falling foul of drink-driving laws rises.

Last autumn the former transport minister moved an amendment to the Road Safety Bill which would have seen drugged drivers penalised more heavily. But it was thrown out of the Commons.

He said: "These new figures are very worrying. Other countries carry out roadside drug tests while the government here is turning a blind eye to the increasing number of young people being killed and injured on our roads.

"I can't understand it when we have the technology here to carry out roadside drug tests."

Within minutes, a hand-held "drugalizer" can detect cannabis, ecstasy and cocaine from a swab of saliva.

Mr Chope added: "Chest hairs can also tell whether there is a pattern of drug use. The police use this test during their own recruitment procedures and it is also used to screen employees such as train drivers.

"People who drive after drinking or taking drugs must realise that they are a menace. The penalties are there but the offenders aren't being detected."

Chief Inspector Rick Dowell, head of Dorset's road policing unit said: "Currently there is no type of approved instrument capable of detecting the presence of drugs at the roadside.

"If a driver shows lack of co-ordination they are arrested, taken to a police station for a blood test and medical examination."