Two men have made UK legal history after being convicted of a drugs-related offence even though the substances involved are not illegal, police said.
Anthony Woodford, 23, and David Lewinson, 44, stood trial after Lewinson was found with 330lb (150kg) of grounded paracetamol and caffeine at Dover docks in Kent.
Although the substances are not illegal, investigators suspected they would be used as cutting agents for heroin, giving the Class A drug a street value of more than £5 million.
The Kent and Essex Serious Crime Directorate launched an investigation and identified Woodford as the organiser of the cross-Channel trip, which led on to a landmark prosecution.
The pair were charged under the Serious Crime Act 2007 with "importing a quantity of caffeine and paracetamol which was capable of encouraging or assisting ... the supply of a controlled drug of Class A".
At Maidstone Crown Court on Monday, a jury found Woodford, of Harlow, Essex, and Lewinson, of Colindale, north London, guilty of the offence.
Today, Detective Sergeant Mat Scott, of the Kent and Essex Serious Crime Directorate, said: "This is the first time in the UK that a successful prosecution has been made when the drug found has not itself been an illegal substance.
"The prosecution were able to prove, beyond doubt, that the huge quantity of paracetamol and caffeine was intended to be used to cut with heroin.
"This has been a successful test case and, therefore, has set a precedent for this type of offence."
Police said that Lewinson drove a white Volkswagen Caddy van out of Dover's Eastern Docks and on to a Dunkirk-bound ferry on April 20 last year.
But he was stopped by border officials when he tried to return a day later - and the ground powder was discovered.
The pair will be sentenced on October 19.