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.

Money seized in drugs raids is often laced with cocaine and finds its way back into general circulation

A study by the Forensic Science Service estimated that every banknote in Britain is contaminated with the class A drug within two weeks of entering circulated. The old cotton banknotes which are being phased out are notorious for picking up substances, which is one the reasons that the Bank of England is moving to plastic notes.

The Drinking Water Inspectorate has also previously warned that the metabolised form of cocaine - benzoylecgonine - is present in tap water, while traces of the drugs are regularly detected in public buildings.

Dr Melanie Bailey, Lecturer in Forensic Analysis at the University of Surrey, said: “Believe it or not, cocaine is a very common environmental contaminant – it is well known that it is present on many bank notes.

“Even so, we were surprised that it was detected in so many of our fingerprint samples.

“By establishing a threshold for significance on a fingerprint test, we can give those tested the piece-of-mind of knowing that whatever the result of the test may be, it was not affected by their everyday activities or shaking hands with someone that had taken drugs.”

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In recent years, investigations have found evidence of cocaine use at St Paul’s Cathedral, the Houses of Parliament and the Bodlein Library at the University of Oxford.

Gordon Ramsay, the chef, claimed that cocaine use is so rife in the restaurant industry that diners have asked him to sprinkle the class A drug over a soufflé and a customer at one of his venues took a plate to the toilet so they could snort lines of the drug.

Around 700,000 people aged 16-59 are estimated to take cocaine every year in Britain and about 40,000 people use heroin but it can be difficult to test drug users from those who have become accidentally contaminated.

To try and combat the problem of false testing, researchers at the University of Surrey have now set a ‘cut-off’ level above which show a genuine drug users.

The Bank of England brought in new plastic notes to avoid substances becoming stuck to them credit: PA Steve Parsons

Researchers showed it was possible using their method to differentiate from someone who had picked up cocaine by shaking hands with a drug user, and the drug user themselves.

Mahado Ismail, lead-author of the paper from the University of Surrey, said: “It’s clear that fingerprint testing is the future of drug-testing.

“There are many factors that set fingerprint testing apart – it’s non-invasive, easy to collect and you have the ability to identify the donor by using the sample. Our study will help to add another robust layer to fingerprint drug testing.”

The new research was published in the journal Clinical Chemistry.