DRUG drivers are more likely to think they can "get away with it" in Scotland because there is no roadside testing or criminal limits, campaigners have warned.

Road safety and motoring groups have expressed disappointment that almost a year after England and Wales enforced tough new drug drive laws, the legislation is nowhere near being implemented north of the Border despite the initiative's apparent success.

Guests at a recent Road Safety Scotland conference were told that there has been a four-fold increase in the number of motorists in England and Wales charged with driving under the influence since the law was introduced on March 2 2015, while the successful conviction rate has nearly doubled from 52 per cent in 2012 to 95 per cent now.

The figures, which have yet to be published officially, also show that Cheshire police force alone has recorded a six-fold increase in arrests for drug driving during the first six months under the new law, which makes it an offence to drive 'over the limit' in relation to 17 illegal and pharmaceutical drugs - mimicking drink driving rules.

Previously prosecutors were required to prove a person's driving had actually been "impaired" by drugs in order to secure a conviction, and this remains the situation in Scotland.

Roadside 'drugalysers' have also enabled police in England and Wales to quickly screen motorists for substances including cannabis and cocaine, while early evidence indicates that the practice is helping to disrupt associated crimes with seizures of stolen goods and drug hauls also up.

However, the Herald understands that a draft copy of the Scottish Government's updated road safety plan, laying out its priorities for the next five years, makes no mention of drug driving. The report is due to be published in the next few weeks.

Neil Greig, the Scotland based head of policy for the Institute of Advanced Motorists, said: "Scotland is leading the way on things like drink drive, with the lower limit, but we're lagging behind on drugs and really missing out on a very useful tool for road safety and crime in general.

"What this drug driving law in England seems to have uncovered is a substantial problem, but it is giving the English police something they can use to fight against it.

"I see no reason why what's happening in England isn't happening in Scotland."

A spokesman for the AA added: "There is a need to catch up because the danger is the perception.

"If you think your chances of being caught and proven to be under the influence [are lower in Scotland], it sends out the message to drug drivers that they stand a pretty good chance of getting away with it."

It comes amid reports that Westminster is poised to roll out Scotland's lower drink drive limit in England and Wales.

Alice Bailey, campaigns officer for road safety charity, Brake, urged the Scottish Government to adopt the new law as soon as possible.

She said: “The significant increase in charges and convictions for drug driving since new laws were introduced in England and Wales last year proves that this law was needed.

"It’s selfish and reckless to get behind the wheel after taking drugs. Every day we see the devastating consequences of crashes caused by drug drivers, through our victim support work. One in five drivers who die in crashes have drugs in their system.

"With Scotland leading the way when it comes to reducing the alcohol limit for drivers we’re surprised action isn’t being taken on roadside drugs testing."

A spokeswoman for the Scottish Government said: “Following prioritising the delivery of a lower drink drive limit, we are considering whether specific drug-driving limits in Scotland would add to the existing powers of police in tackling those who drive after taking drugs and will be informed by the experience and lessons learned from implementation in England and Wales.”