Experts warned that the protective effect against heart disease did not get bigger the more people drank but the risk of cancer, accidents, mental health problems and liver cirrhosis do increase with high consumption.

Others said the study was 'flawed'.

The study, published in the journal Heart, was conducted in Spain, one of the world's largest producers of wine but with one of the lowest death rates from heart disease.

The authors found that drinking between five and 30 grams of alcohol a day, the equivalent to less than one UK unit to almost four units or up to one large glass of red wine, reduced the risk of developing heart disease by half.

The protective effect did not increase significantly the more people drank and those with the highest consumption,11 units or more – the equivalent to over one bottle of red wine a day – still had a 50 per cent lower chance of heart disease.

The effects were seen for all forms of alcohol and were not limited to red wine, which previous research has suggested was especially protective for the heart because of substances in the skins of red grapes.

The results were women followed a similar trend but were not significant because of relatively few women in the study developing heart disease so the data could not be relied upon to be accurate.

The study conducted by a team of doctors and epidemiologists at Government departments and Universities across Spain, involved questioning more than 41,000 people aged between 29 and 69, who did not have heart disease when enrolled and who were followed up for an average of ten years.

Prof Mark Bellis, director of the centre for Public Health at Liverpool John Moores University, said: "The message from this study is that the coronary protective effect of alcohol begins at a relatively low level of consumption and does not significantly increase the more people drink. The protective effect is in place at around one quarter of a normal glass of wine daily.

"The danger is that this study will be interpreted that there are no health harms from drinking large amounts of alcohol but you have to be very careful looking at one disease with alcohol consumption. Our work has looked at more than 40 different diseases and the risk of almost all of them increases with high consumption of alcohol, particularly cancers."

Prof Robert Sutton, Professor of Surgery at the University of Liverpool, said: "This study suffers from several flaws, so cannot be taken to suggest that high levels of alcohol intake can improve health.

"This new study was based on self-reported information in which those drinking more stated they had less heart disease, but those drinking more would probably be less likely to see doctors and have heart disease identified.

"Surprisingly, the authors state that determining what type of alcoholic beverage has been consumed is actually of no public health significance, but many would disagree. Nor was there any attempt evident to determine the pattern of drinking – less frequent, higher doses are likely to be more harmful to some parts of the body than others.

"Most importantly, all other alcohol-related diseases were completely ignored so that a highly biased view of the effects of alcohol results."

A spokesman for the Department of Health said: "A wide range of studies, including the World Health Organisation summary of the evidence, find many negative effects of drinking above the lower-risk recommended levels. This includes an increased risk of stroke and cancer. Research also shows the harmful effects of drinking excessively on heart disease.

"We will consider this particular report in full, but it is important to note this is currently one study amongst a wide range of published research into the relationship between alcohol and heart disease. It needs to be looked at alongside other research and to be considered within the whole body of evidence on this topic."

-The Telegraph UK