DRUG users across Yorkshire have been warned about deadly batches of heroin on the streets.

A police investigation, following a number of drug deaths across Yorkshire, Humberside and Cleveland, has found dealers are deliberately contaminating Class A drugs with Fentanyl and Carfentanyl.

The substances are massively more potent than street heroin, and have been found in batches across the region. Tests by West Yorkshire Police are continuing to find their source.

A force spokesman said Fentanyl - an anaesthetic more powerful than morphine - was “100 times more potent than street heroin, with Carfentanyl 100 times more potent than that”. Carfentanyl is used on animals.

Detective Chief Inspector Jim Dunkerley said: “We are urging those people who regularly use heroin and particularly those who purchase their drugs via street suppliers to be extremely cautious in relation to what they are taking.

“Typical symptoms of a Fentanyl overdose include slow and difficult breathing, nausea and vomiting, dizziness and increased blood pressure. Anyone experiencing any unusual symptoms after taking drugs should seek immediate medical attention. We would recommend any heroin addicts to consider making contact with drug addiction services to seek their support.”

Police across Yorkshire and Humberside are working with the National Crime Agency and NHS England to spread the warning to drug users about the dangers of the contaminated batches.

Help and support is available from all police forces, the NCA and public health organisations.

Anyone with information which could help police should phone 101 or Crimestoppers, anonymously, on 0800 555111.