NEW laws to stop the menace of motorists under the influence of drugs getting behind the wheel have been welcomed by the mother of a girl killed by a speeding driver.

But another campaigner says that while the legislation, which became law on Monday, is to be applauded, police must ensure they don’t let up on anyone unfit to drive.

For the first time motorists face prosecution if they exceed limits set for the presence of eight illegal drugs.

Police will use ‘drugalysers’ to screen for cannabis and cocaine at the roadside and for other drugs such as ecstasy, LSD, ketamine and heroin at police stations.

Drivers on medication, including diazepam, temazepam, methadone and morphine, who have taken over the prescribed dose will also be prosecuted.

The new rules run alongside the existing law which makes it illegal to drive while impaired by any drug, with a fine of up to £5,000, up to six months’ jail and at least a one-year driving ban.

Jane Hofmeister, of Taunton, whose daughter Amy was killed by a driver racing his girlfriend in another car – both were jailed for causing death by dangerous driving – welcomed the new law.

She said: “Drug-related accidents are never really reported, but they do happen.

“People should only drive if they’re completely clear and free to do so and don’t have any drugs in their system.

“Anything that helps deter people from abusing what they do behind the wheel is a good thing.”

Nick Smith, who has campaigned against the sale of legal highs in Taunton, said: “Anything that makes driving safer is good.

“If they can find a way to test for legal highs as well, that would be excellent.

“I’ve seen legal high users walking round town - there’s no way they’d be safe behind the wheel.

“I welcome the new law so long as it doesn’t weaken police action against drivers on legal highs.”

National policing lead for roads policing Chief Constable Suzette Davenport said: “Improving the tools that officers can use to better detect those who drive whilst impaired by drugs will immeasurably enhance our ability to keep the roads safe.

“Forces will be training their officers and making decisions locally about the best way to implement the new legislation.”

Policing minister Mike Penning said: "These new mobile drug screening devices will help the police obtain evidence quickly and use the new drug-driving offence to bring those that put themselves and others on the roads in danger to justice."