A man died from an enormous caffeine overdose after snacking on high-energy mints - each of which is as powerful as a can of Red Bull.

John Jackson, 40, ate Hero Instant Energy Mints, unaware they could kill him. Each mint contains 80mg of caffeine, equivalent to a can of Red Bull, but are sold alongside normal mints.

Coroner Robin Balmain recorded a verdict of accidental death but said he intends to write to the Department of Health highlighting the dangers of energy sweets.

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He said at the hearing: “It seems to me to be something the authorities need to know about. It is up to them to take any action. This is potentially a dangerous situation. I am as certain as I can be that Mr Jackson did not know he was exposing himself to danger.”

Dr Dragana Cvijan, a pathologist, told the court that 79 milligrammes of caffeine has been known to cause death and that a post mortem revealed Mr Jackson had 155 milligrammes in his system when he died.

Mr Jackson was a heavy drinker and had cirrhosis of the liver which would have limited his liver’s ability to process toxins but it was the caffeine overdose that killed him, the pathologis said.

She told the hearing: “To my surprise the immediate cause of death was not cirrhosis, but through caffeine overdose. The post mortem showed other drug traces, but not enough for the final outcome.

“I am sure this is the first time in my experience we have come across what was literally a caffeine overdose. It was confirmed by experts in this field. The amount found was really excessive and entirely in keeping with death due to excess caffeine in the blood. If the liver was not functioning properly that would contribute to the final outcome.”

Mr Jackson, a former painter and decorator, bought a £4 tin of 12 sweets from his local shop. He was found dead in his flat by his former partner in Darlaston, near Birmingham, on 2 May this year.

Rebecca Court, his stepdaughter, called for the product to be banned, after the coroner criticised its manufacturer. She said: “On the box it said one tablet equals one can of energy drink. It’s unbelievable. They’re classed in the same place as Polos and Extra Strong Mints. I’m scared to drink coffee now.”

Birkenhead-based Hero Energy said that it highlighted the risk with prominent warnings on packaging and shelves. In a statement, directors Paul Hayes and Steve Hones said they “fully understand” the dangers and risks of caffeine and that the packs advise no more than five be consumed in 24 hours.

The inquest was not told how many Mr Jackson ate but the manufacturers said that he would have had to have eaten “over 300 of our mints, which is staggering” to have the levels of caffeine he had in his blood.