Police have sent an unequivocal message to motorists after two drug-drivers claimed to be ignorant of the law.

Last week, two men were banned from driving after testing positive for an inactive metabolite consistent with cocaine use – despite their systems containing no trace of the drug itself.

Although cocaine circulates through the body in a matter of hours, benzoylecgonine (BZE) can remain detectable for days after being formed by the liver.

Magistrates heard that both defendants were oblivious of committing a motoring offence when pulled over in routine stops.

In 2015, it became an offence to drive with more than 10 micrograms of cocaine and 500mcg of BZE per litre of blood.

Stephen Debenham, 28, of Periman Close, Newmarket, took cocaine “a few days” before his Ford Fiesta was stopped in Exning Road on November 18 – but a sample detected no less than 800mcg of BZE in his blood.

Solicitor Lyndon Davies said: “Many young drivers take drugs and don’t know it remains in their system. But that’s the law, and he fell foul of it on this occasion.

“In reality, you simply can’t take it at all if you intend to drive.”

Daniel Currell’s BMW 325 was stopped nearby the next day.

The 20-year-old, of Fairfields Crescent, St Ives, had 384mcg of BZE in his blood and told police he had recently taken cocaine.

Solicitor Shelley Drew said: “He went out with friends and used cocaine at about 10pm the previous evening, before driving about 18 hours later.

“It wasn’t the cocaine that remained, but the derivative thereof, which is still prohibited.

“Just how long it remained came as something of a surprise.”

Both men were banned for the minimum 12 months.

During December’s drink and drug-driving campaign, 67 drivers failed 194 drug tests in Suffolk.

Sergeant Scott Lee-Amies, of the Norfolk and Suffolk Roads Policing unit, said: “Driving with drugs or alcohol in your body impairs your ability to drive effectively and puts you and other road users at risk. We continue to target drivers who flout the law and ignore this advice.

Roadside drug tests can also detect eight prescription drugs that impair driving in high doses.

Sgt Lee-Amies said: “Many of these drugs can be detected in the system for several weeks. It only takes a small amount of these substances to breach the limit.”