A new anti-drug law will come into effect in England and Wales on 2 March 2015.

So why is this new legislation being introduced?

The new law aims to catch and punish those who put the lives of others at risk while driving under the influence of drugs.

So is it just illegal drugs that the new law will outlaw?

No, as well as banning driving while under the  influence of illegal drugs, the new law will include some prescription medicines.

So how do I know whether the new laws will affect me? 

The new legislation sets very low levels for eight well known illegal drugs, including cannabis and cocaine, but also includes eight prescription drugs, where the levels have been set much higher.

Most of them, including Temazepan and Diazepam, are used for treating conditions such as anxiety but the list also includes methadone, a heroin substitute and pain medication, and morphine, a powerful opiate also used for pain relief.

The good news is that prescribed doses do not exceed the limits for legal drugs, so most patients should still be safe to drive.

Those who are unsure are advised to seek the advice of a pharmacist.

So what recourse would a driver have if a prescribed dose caused them to fall foul of this new legislation?

The new legislation will provide drivers with a medical defence if they have been taking medication as directed and are found to be over the limit but not impaired.

Road Safety Minister, Robert Goodwill, said “Drivers who are taking prescribed medication at high doses [are advised] to carry evidence with them, such as prescriptions slips, when driving in order to minimise any inconvenience should they be asked to take a test by the Police.”

So is this new legislation being welcomed?

Ed Morrow, Campaigns Officer for road safety charity Brake said: “This much needed progressive move by Government will make it much easier for Police to deal with illegal drug-drivers”.

“We are confident that the necessary measures are in place to ensure drivers who take prescription medication are not unfairly penalised”.

“However, many prescription medications can have a negative effect on your ability to drive safely, and there is a worrying lack of awareness of this among the public.”