Claire Beacham, regional manager for the Essex-based charity Open Road, has seen the rise of nitazenes first hand in recent months.

She said: “They’ve spread like wildfire really because opioids aren’t getting into Europe anymore, so people are making their own which is where the synthetics come in.”

She said it was particularly “dangerous” and “frightening” because nitazenes were being mixed with a wide range of illicit drugs, not just heroin and other opioids.

“People are taking recreational drugs or party drugs and its contaminated with nitazenes, and there’s different types, but some are 100% stronger than street heroin,” she said.

The charity gives out naloxone antidote kits and training on how to administer it to drug users, as well as their friends and family, night time venues and on the organisation’s SOS buses.

Claire and her team work with local health bodies, the police, housing services and anyone in direct contact with drug users to pass on intelligence they receive about contaminated batches of drugs.

She said publicly available drug testing was needed to combat the problem, a move that would require “trust” and “breaking down barriers” to give drug users the confidence to come forward.