The figures show fentanyl was responsible for 113 deaths over the last 14 months – eight deaths a month compared with an average of 2.7 a month in 2015.
Meanwhile figures from NHS Digital show the number of fentanyl prescriptions have doubled to 1.2 million.
Separate research shows the UK is now the largest host of dark web fentanyl sales in Europe, behind almost 10 per cent of illicit world sales and an average of more than 300 a month.
The revelations follow repeated warnings from the National Crime Agency to be vigilant about fentanyl after the drug was associated with thousands of overdose fatalities and addiction in the US, including the deaths of singers Prince last April and Tom Petty in January.
David Raynes of the National Drug Prevention Alliance said: “Fentanyl is the most dangerous illicit drug on the current horizon.
“It has killed many people in the States, many here in the UK and is likely to kill many more.”
Police say it is difficult to stem the tide as fentanyl is relatively simple to make in a home laboratory and also available through the dark web, originating mainly in China and Hong Kong.
Earlier this month Kyle Enos, 25, of Newport, south Wales, was jailed for eight years for exporting and selling fentanyl using the internet.
Robert Fraser, 18, who was found dead in his bedroom in Deal, Kent, in November 2016, was given fentanyl as a “freebie” by his dealer when he went to buy cannabis, his mother Michelle said.
“Fentanyl is a killer and the drug dealers are playing Russian roulette with our lives… my child died from it,” she said.
Another trend is the abuse of the powerful sedative Xanax.
Experts said while the use of the highly-addictive benzodiazepine drug, used to treat anxiety, was still relatively small, it had risen sharply in the last year, with pockets of England affected.
It should be obtained only on private prescription but pills can be bought from street dealers, online pharmacies or the dark web for as little as £1 each.
Withdrawal symptoms include blurred vision, muscle pain and seizures.
Official figures show overall drug abuse deaths are at their highest level since records began in 1993.
Some 2,593 people died in England and Wales in 2016, nearly 60 per cent higher than 10 years ago – meaning one in every 200 deaths is from drug misuse.
There is thought to be an unreported but significant number of deaths linked to drug-related violence.
It was revealed last week the London Bridge terror attackers took powerful mood-altering steroids before killing eight people and Westminster Bridge killer Khalid Masood also took steroids.
Meanwhile the Medicines and Healthcare Regulatory Agency is cracking down on the diversion of prescription-only medicines, especially tranquillisers including benzodiazepines, on to the criminal market.
Medicines worth an estimated £115-200million were diverted to criminals between 2013 and 2016.