Cocaine is now so prevalent in society that one in 10 people who have never used the drug have traces on their hands, a new study has shown.

Researchers at the University Surrey tested the fingerprints of 50 drug free volunteers and 15 drug users who had taken cocaine or heroin in the past 24 hours.

Around 13 per cent of fingerprints of those who had never used the drugs were found to contain cocaine, while one per cent contained a metabolite of heroin.

The findings throw up concerns that people could be wrongly accused of drug use simply because the environment is contaminated.

In 2015, bus driver Alan Bailes won a claim for unfair dismissal after he was sacked for failing a drugs test because he handled banknotes which contained traces of cocaine.