People in England drink the equivalent of 12 million bottles of wine per week more than was estimated, according to new research.

Surveys measuring drinking habits in England have failed to account for around 40% of the alcohol sold, says journal BMC Medicine.

This is thought to be because many surveys do not account for drinking on special occasions. Including special occasion drinking added 120 million more units to population’s weekly alcohol total.

Dr Mark Bellis, the report’s author, said: “Nationally, we underestimate how much we drink – and as individuals we can turn a blind eye to our heavier drinking periods when we calculate personal consumption.”

The equivalent of three pints of beer (or more than three-quarter’s of a bottle of wine) per drinker per week goes unaccounted for.

Researchers asked over 6,000 members of the public about their normal drinking patterns, as well as on special occasions, including summer holidays and weddings.

In almost every category – based on age and levels of consumption – drinkers reported increased consumption on special occasions.

25 to 35-year-olds had the biggest increase, as well as having the highest typical consumption.

People in this category drank an extra 18 units of alcohol per week on special occasions.