The growing popularity of New World wines and strong lager from the Continent has prompted government statisticians to overhaul the system for measuring alcohol consumption for the first time in 30 years.

The result is that the nation’s drink problem is even worse than thought.

Most wines are now in the 11.5 per cent to 13.5 per cent category. When surveys of drinking were first carried out, it was assumed that wine was 9 per cent proof.

Under the new system, alcohol consumption in 2005 was actually 14.3 units a week per person, compared with 10.8 units under the old measure.

Women’s average intake shoots up by 45 per cent to 9.4 units per week under the new measurement, largely because they drink more wine than men.

But men’s consumption is much higher too, up by 26 per cent from 15.8 to 19.9 units on average per week, the Office for National Statistics said.

The revised figures bring both sexes closer to the Government’s recommended weekly limit of 14 units a week for women and 21 units for men.

Super-strong wines from the New World were largely responsible for the change. Australian chardonnay and New Zealand sauvignon blanc are very popular with women, which is why their consumption has been so greatly underestimated, statisticians said. “Applying the new methodology to 2005 data shows that there has been some undercounting of the number of units in certain types of drinks — predominantly wine, but also, to a lesser degree, beer, lager and cider,” the report said.

As well as the increased strength, the wine glasses used in bars are often larger than the original 125ml measure. A survey carried out in March found that the average size of a glass of wine was 169ml, the ONS report says. All future ONS surveys will ask respondents about wine glass sizes.

The ONS has also updated its estimates of the alcoholic strength of beers, lagers and ciders. A small 125ml glass will count as 1.5 units of alcohol, rather than one, while a medium 175ml glass will count as two units and a large 250ml glass as three units. Until wine glass size data are available, the ONS will assume that one glass of wine equals two units. Half pints of beer, lager and cider will still count as one unit of alcohol. But small and large cans should be increased to 1.5 units and two units respectively, the ONS said. Strong beers of 6.5 per cent will be assessed as two units for a small can and a half pint, while a large can will count as three units.

When drinking surveys were first carried out in the 1970s it was assumed that a glass of table wine, a single measure of spirits or half a pint of beer equalled one unit of alcohol.

Applying the new criteria to the 2005 General Household Survey lifts women’s alcohol consumption from 6.5 to 9.4 units on average per week.

The changes were criticised by the drinks industry for confusing consumers. “Today’s report only adds to the confusion from the Government on sensible drinking,” said Jeremy Beadles, chief executive of the Wine and Spirit Trade Association. “The fact remains that alcohol consumption is decreasing and more young people are abstaining from drinking at all.”

David Poley, chief executive of the Portman Group, a drinks industry body, said that excessive drinking was also on the decline. “Over the last five years ONS figures show the number of adults drinking excessively has fallen and fewer 16 to 24-year-olds are now binge-drinking,” he said.

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