Drivers who get behind the wheel while under the influence of controlled drugs should be treated with zero tolerance, a road safety charity has said.

Brake said drug-driving is a major problem, hampering driver reaction time and encouraging dangerous behaviours that put the individual and other road users at risk.

It is now calling on the Scottish Government to crack down on "dangerous and potentially deadly" motorists who take drugs.

In 2014, Scotland led the way by introducing a lower limit for drink-driving than the rest of the UK, at 50mg of alcohol per 100ml of blood compared to 80mg.

Brake said it believes it is now time to take the next step by introducing a similar drug-driving law.

The charity is urging ministers to follow the example in England and Wales where in 2015 a zero-tolerance drug-driving ban was introduced, making it an offence to drive after taking certain controlled drugs, both illicit and some prescription-only substances.

Since the ban was introduced, drug-driving arrests have soared in police forces across England and Wales.

Between March 2015 and April 2016, almost 8000 people were arrested for the offence and the number of convictions for careless driving under the influence of drugs also rose from 1039 in 2014 to 1490 in 2015.

Gary Rae, campaigns director for Brake, said: "I want to send the First Minister a clear message that her Government needs to root out dangerous and potentially deadly driving by introducing a drug-driving law.

"There's evidence that the law is working in the other nations of the UK and will work in Scotland."

The latest available UK figures, from 2015, show 62 fatal crashes were a result of impairment by illicit drugs.

In a survey last year by Brake and Direct Line, 7% of respondents admitted driving while under the influence of drugs, with over half of those doing so on a weekly basis.