Bristol has registered the highest concentration of cocaine traces in a Europe-wide study of sewage.
Researchers examined wastewater in dozens of cities around the continent to explore drug-taking habits.
In order to assess cocaine levels, experts tested samples for benzoylecgonine (BE), which is produced when the body breaks down the class A substance.
The average daily concentration of benzoylecgonine in Bristol’s wastewater was 969.2mg per 1,000 people in 2018.
This was up from 754.7mg in the previous year.
Amsterdam recorded the second highest figure in 2018, with 932.4mg, followed by Zurich (856.0mg), Antwerp Zuid (771.8mg) and Barcelona (733.2mg).
Bristol was the only UK city participating in last year’s research.
London’s wastewater, which has previously topped the cocaine chart, was not included.
The project analysed wastewater in 73 cities in 20 European countries, covering a total population of around 46 million, in March last year.
As well as cocaine, wastewater was examined for traces of amphetamine, MDMA and methamphetamine.
The 2018 findings pointed to increases in MDMA, or ecstasy, traces and amphetamine residues in several locations.
Methamphetamine, which has historically been concentrated in the Czech Republic and Slovakia, now also appears to be present in Cyprus, the east of Germany, Spain and northern Europe, according to the report.
The analysis also indicated that use of MDMA and cocaine rose sharply at weekends in most cities.