Forensic Drug Analysis on banknotes

Forensic Scientists have stopped a legal loophole that had allowed drug dealers to shrug off incriminating forensic evidence in court.

During forensic investigations police use cocaine found on bank notes as evidence that a criminal handled large amounts of the drug. But in court defendants often claim the contamination is simply due to them living in an area of high drug use.

But this is no longer to be the case as this new study has revealed, because contamination is evenly distributed on bank notes throughout the country. It has already been used in several court cases involving drug crime.

"Across the country contamination was on average approximately the same. So geographical location was not important," said Gavin Lloyd at Bristol University who carried out the study.

Almost every bank note circulating across the UK is contaminated with tiny amounts - of the order of a billionth of a gram of cocaine, according to Abi Carter whose company Forensic Resources carries out drug analyses for British police authorities.

“Cocaine sticks to bank notes particularly well because the typical size of particles is roughly right to fit in between the fibers of bank notes. Most notes have probably not come into direct contact with cocaine - for example when someone rolls them up to snort the drug - but bank sorting machines even out contamination by moving the drug between lots of notes. Traces of Cannabis and heroin are typically found on around 5% of bank notes”

If cash seized by police investigating drug crime or money laundering has unusually large quantities of the drug though this can be vital evidence for securing a conviction. But the team wanted to check that living in a high crime area or near a port where drugs are smuggled into the country does not mean that money in circulation legitimately is not also highly contaminated.

They picked eight locations around the country including Oxford, Folkestone and Cardiff that varied in their crime rate, affluence and proximity to a port. At each location they tested 100 notes from a local bank and found that levels of cocaine contamination did not vary around the country. The team was presenting their research at the British Association Festival of Science.

Further information:

If you require further information on drug analysis, drugs on bank note analysis or any other drug expert witness services please contact Forensic Resources ltd on 02920 647 043