The number of people admitted to A&E departments after heavy drinking has tripled since the introduction of 24-hour drinking, a report has found.
Admissions for drink related problems to one London hospital rose from nearly three per cent a month before 24-hour drinking to eight per cent a month after the liberalisation.
Published in the Emergency Medicine Journal (BMJ), the authors of the report said 24-hour drinking had the opposite of its intended effect, which was to discourage binge drinking and reduce anti-social behaviour at pub closing time.
However, the government questioned the relevance of the research, which took data from just one emergency room for a relatively brief period.
The researchers studied admissions to St Thomas' Hospital in London. All adults over 16 who had been drinking were included in the survey.
In March 2005, eight months before 24-hour drinking came into effect, there were fewer than 2,700 overnight visits and the number of people with alcohol related problems was fewer than three per cent.
By March 2006 there were more than 3,100 overnight admissions and eight per cent of those had alcohol related problems.
The number of visits following drunken assaults also doubled.
The authors wrote: "We feel that our findings are likely to be representative of inner city [emergency care departments] in the UK.
"If reproduced over longer time periods and across the UK, as a whole, the additional numbers of patients presenting to [emergency care], with alcohol related problems could be very substantial."
The shadow health secretary Andrew Lansley pointed out that, if the findings were replicated across the UK, the cost to the NHS would be massive.
The Department of Health (DoH) said it was important to remember the study was only based on one A&E department.
A DoH spokesman said: "Since the change in licensing laws, A&E departments have continued to perform exceptionally well.
"The government's renewed alcohol policy aims to forge a clearer national understanding of what is acceptable drinking behaviour in order to reduce the harm that alcohol causes to individuals, families and communities.
"It sets out a new approach to achieve significant and measurable reductions over a sustained period in the harms caused by alcohol."
The Liberal Democrats, however, said the report was a damning indictment of the government's attempts to curb binge drinking.
Don Foster, Lib Dem culture spokesman, said the government had ignored warnings of the adverse affects of changing the licensing laws.
"The shocking increase in alcohol fuelled violence raises very serious questions as to why the government has decided to stop keeping records on this type of offence," Mr Foster said.