Motorists in Scotland will be subject to drug driving limits and roadside testing from 21 October this year, the Scottish Government announced this morning.

Ministers are promising a "zero tolerance" approach to eight drugs most associated with illegal use, including cannabis, heroin and cocaine, with limits set at a level where any claims of accidental exposure can be ruled out.

A list of other drugs associated with medical use will have limits based on impairment and risk to road safety.

Offenders face a minimum 12 month driving ban, up to six months in prison and a fine of up to £5,000, as under the existing law which makes it an offence to be in charge of a motor vehicle while unfit to drive through drink or drugs. The new law, which will operate alongside the existing offence, will make it easier to hold drug drivers to account as there will no longer be a requirement to prove that someone was driving in an impaired manner.

Currently, when police suspect drug driving, they can carry out a roadside field impairment test. If the individual fails the test they can be arrested and taken to a police station for further tests. A doctor must certify that the person is, in their opinion, impaired to the extent that they are unfit to drive.

The UK Government introduced provision in the Crime and Courts Act 2013 which made it an offence to drive under the influence of different drug types when over a specified limit. The ability to provide specified limits for drugs is now devolved.

Regulations laid in the Scottish Parliament, subject to MSPs’ approval, will permit prosecutions where different drug types are found to be above specified levels.

The drugs which will have a zero tolerance limit are benzoylecgonine; cocaine; cannabis and cannabinol; ketamine; LSD; methylamphetamine; MDMA (ecstasy); and heroin and diamorphine.

Drugs with medical uses which will have limits based on impairment are clonazepam; diazepam; flunitrazepam; lorazepam; methadone; morphine; oxazepam; and temazepam.

A separate approach will be taken to amphetamine, balancing its legitimate use for medical purposes against its abuse.

Chief Inspector Stephen Innes of Police Scotland commented: "The devastating impact of drug driving on victims, communities and users themselves cannot be understated.

"This new legislation will significantly enhance our ability to detect and deter motorists engaging in this extremely risky driving behaviour."