New legislation is due to come into force to make it easier for drug-drivers to be prosecuted.

Motorists who get behind the wheel after taking drugs are the target for a new road safety crackdown across the county.

The legislation came into force on March 2 and sets legal limits for how much of a substance, both illegal drugs and prescription medication, motorists can have in their system while driving.

A new device, DrugWipe, has been approved to allow officers to test within 10 minutes if motorists have taken cannabis or cocaine.

Any drivers who fail the tests will be arrested and taken to a police station. If they refuse to give consent for a further blood test they face being prosecuted.

Illegal drugs covered by the new rules include cannabis, cocaine, ecstasy, heroin and ketamine and medicinal drugs such as diazepam, methadone and morphine.

National statistics suggest one in six drivers who die in crashes in the UK have traces of illegal drugs in their systems.

Inspector Stewart Goodwin, Surrey and Sussex road policing unit, said: "Drug-driving is a widespread but often hidden menace across the country. You don't have to be on illegal drugs to be unfit to drive, many prescription or over-the-counter drugs can also impair your ability to drive.

"In the same way that we take a zero tolerance approach to drink-driving, we will also not tolerate drug-driving. Driving under the influence of drugs puts not just the offenders and their passengers at risk but everyone else on the roads as well."