David Cameron’s plans to introduce a minimum unit price on alcohol are based on flawed research and will punish moderate drinkers, according to a new report by a leading think-tank.

The Adam Smith Institute tore apart research from academics at Sheffield University that has provided the backbone for the controversial plans.

The university used a computer called the Sheffield Alcohol Policy Model to determine that a minimum unit price would lead to fewer alcohol-related deaths and hospital admissions in the UK.

Supporters of the scheme have used this research as their primary evidence regarding its effectiveness.

But Adam Smith Institute statistician John Duffy, a former government health official with 40 years’ experience as a statistician working on alcohol-related problems, said this “single” model used to back minimum unit pricing is “flawed”. 

He added: “Predictions based on the Sheffield Alcohol Policy Model are entirely speculative and do not deserve the exalted status they have been afforded in the policy debate.”

He accused the Sheffield University paper of being based on “unreasonable assumptions which render its figures meaningless”.

Duffy warned the move could lead to a growth in the market for illicit alcoholic drinks, push poorer drinkers into poverty and fail to acknowledge the potential health benefits of moderate drinking

He said: “Among the problems with the Sheffield model is its false assumption that heavy drinkers are more likely to reduce their consumption of alcohol as a result of a price rise.

“Its calculations are based on controversial beliefs about the relationship between per capita alcohol consumption and rates of alcohol related harm.

“Its assumptions about the relationship between price and consumption have frequently been refuted by real world evidence.

“The Sheffield model provides figures without estimates of error and ignores statistical error in the alcohol-harm relationship.

“Data is drawn from different populations and applied to England and Scotland as if patterns of consumption and harm are the same in all countries.

“When data is not available, the model resorts to what is essentially numerology. Insufficient data is provided for the model to be recreated and tested by third parties.

“The model ignores the likely effects of minimum pricing on the illicit alcohol trade, it disregards the health benefits of moderate drinking and fails to take account of the secondary poverty created by regressive price rises.”

Meanwhile, another study revealed Cameron will lose votes if he pushes ahead with plans to introduce a minimum unit price on alcohol and ban supermarket multi-buy deals.

Research conducted on more than 2,000 consumers by advisory and restructuring specialist Zolfo Cooper showed 60% were against the plans.

Zolfo Cooper partner Paul Hemming said: “Many pub and bar operators are having the life squeezed out of them by a combination of cheap supermarket booze and escalating duties. The government will not want to become even more unpopular by increasing supermarket prices so the focus needs to be on getting a fairer deal on VAT and duties.”

Further research published in the journal BMC Public Health on Saturday concluded the public was sceptical that minimum pricing would reduce alcohol consumption and feared it would punish moderate drinkers, and a government source told The Independent there is widespread opposition within the Cabinet to the scheme.

But Cameron appears determined to introduce the controversial measure and is set to launch a long-awaited consultation on Wednesday that will include three options for a minimum unit price – 40p, 45p or 50p.

The health lobby has backed the scheme. The Alcohol Health Alliance, whose members include the British Medical Association and the Royal College of Nursing, argued a unit price of 50p will protect the heaviest drinkers and those around them, including children.

But Miles Beale, chief executive of the WSTA, said: “It is hard to understand why the Government is pushing ahead with the consultation now, when there is a wall of opposition in Europe, a legal challenge in Scotland, a lack of any real evidence to support minimum unit pricing and concerns raised from within Cabinet itself.

“Minimum unit pricing and the proposed restrictions to promotions will unfairly punish millions of consumers and businesses in the UK, while doing nothing to tackle the root causes of alcohol misuse.

“It raises serious questions about who Mr Cameron is listening to and why he is pushing ahead.”