A warning has been issued about “pocket money” prices for alcohol, with strong booze on sale in London at just 16p per unit.

The Alcohol Health Alliance (AHA) has condemned how cheaply drinks such as high-strength white cider, which is claimed to be mostly drunk by dependent and underage drinkers, are being sold by supermarkets and off-licences.

It comes after a study found three-litre bottles of 7.5 per cent Frosty Jack’s cider on sale for £3.49.

With each bottle containing 22.5 units of alcohol, the cost per unit was just 16p at Bargain Booze stores in London – making it the cheapest drink on sale in the UK found by researchers who analysed 480 products.

The AHA team also found a wide range of cheap booze being sold by major supermarkets - including Asda, Tesco and Sainsbury's.

Their report said: "Both Asda and Tesco were found to be selling perry at 19p per unit, while Morrisons were selling cider at 20p per unit and Sainsbury's stocked perry at 22p per unit.

"In our research, we also found an abundance of summer-focused promotions. The promotions included deals on multi-packs and free giveaways with alcohol purchases, enticing people to buy."

The report said that for the cost of a standard off-peak cinema ticket (£8.24), people could buy 7.5 litres of the cheapest white cider - the equivalent of 53 shots of vodka.

The study went on: "The minimum hourly wage for those aged under 18 is £3.87.

"After just an hour's work, you would still have 38p change after buying a three-litre bottle of Frosty Jack's containing 22.5 units of alcohol.

"For the cost of a monthly Netflix subscription at £7.49, you would have change from buying two three-litre bottles of Frosty Jack's.

"Today, £10 will not buy you a large Domino's pizza, but you would have a penny left over from a 700ml bottle of 40 per cent Putinoff vodka at £9.99."

The report concluded: "Cheap booze can be found on every street corner. Fundamentally, very little has changed since the last report was carried out five years ago.

"While the lowest price we report is 16p per unit, we found a broad range of products on sale for 25p or less, which is half the 50p minimum unit price recommended by health bodies and alcohol charities.

"At the cheapest price per unit for white cider (16p), the low-risk drinking limit of 14 units per week for both men and women could be purchased for just £2.24."

Chairman of the AHA and former president of the Royal College of Physicians, Professor Sir Ian Gilmore, said: "In spite of a government commitment to tackle cheap, high-strength alcohol, these products are still available at pocket money prices.

“Harmful drinkers and children are still choosing the cheapest products - predominantly white cider and cheap vodka.

"We need to make excessively cheap alcohol less affordable through the tax system, including an increase in cider duty. It's not right that high strength white cider is taxed at a third of the rate for strong beer.

"In addition, we need minimum unit pricing. This would target the cheap, high strength products drunk by harmful drinkers whilst barely affecting moderate drinkers, and it would leave pub prices untouched."

Each year, there are almost 23,000 deaths and more than one million hospital admissions related to alcohol in England.

More than two-thirds of alcohol sold in the UK is purchased in supermarkets and off-licences.

Here are the London figures for the cheapest brands of alcohol identified by the Alcohol Health Alliance.

They show the type of alcohol, the premises, the brand and the price per unit.

Beer/lager: Aldi (Galahad, 4x400ml) 28p

Cider: Bargain Booze (Frosty Jack's, 3l) 16p

Vodka: Lidl (Rachmaninoff, 700ml) 38p

Wine: Lidl (Own brand, 3l) 32p

Perry: Morrisons (Own brand, 1.5l) 24p