People who take over the counter medicine and drive could find themselves committing a criminal offence.
New legislation that came into force on Monday (March 2) sets legal limits for how much of a substance - both illegal drugs and prescription medication - motorists can have in their system while driving.
And a new device has been approved that will allow officers at the roadside to test if a motorist has taken cannabis or cocaine.
The DrugWipe system allows officers to determine in less than 10 minutes whether motorists have the illegal substances in their body using a swab from inside a driver’s cheek.
Those over the limit face a minimum 12-month driving ban, a criminal record, and a fine of up to £5,000, or up to six months in prison, or both. Critics believe many people could be caught out by taking medication such as cough mixture, which contains codeine. Officers no longer need to prove that a motorist is fit to drive - just that the motorist has an illegal level of drugs in their system while driving. Any drivers who fail the tests will be arrested and taken to a police station where they will be asked to consent to a sample of their blood being taken.
That blood will then be sent away to be examined and if illegal levels of a drug are found, the motorist faces being prosecuted for drug-driving. If the driver refuses to give consent, they face being prosecuted for the offence of failing to provide a sample of blood for analysis.
The change in the law is designed to make it quicker and easier for drug-drivers to be prosecuted.