Super-sized servings of sauvignon blanc, giant goblets of grenache: wine glasses in Britain's bars are larger than ever and deepening the country's problematic relationship with alcohol, lawmakers and health officials warn.

Huge measures of wine and a glut of cheap alcohol on sale at supermarkets are fueling a worrying rise in problem drinking among adults, particularly women, authorities say.

Britain has won notoriety for reckless drinking among the young. Drunken, brawling teens and twentysomethings have become a familiar sight in town centers. Relaxed laws mean pubs whose opening times used to be strictly regulated can now serve drinkers round the clock.

The minimum drinking age in pubs is 18, but lawmakers say the crisis of excessive drinking is no longer confined to youth. They warn a steady rise in alcohol intake among older adults — both in bars and at home — could have a calamitous impact on the nation's health.

Some parliamentarians are putting it down to the size of the glass.

"Almost by stealth, we have ended up drinking much more than we used to in the past — everyone is susceptible to it," lawmaker Norman Lamb told The Associated Press.

Lamb, the opposition Liberal Democrat party spokesman on health, claims almost all pubs have ditched the once-standard size wine glass which held 4.2 fluid ounces. Instead, they offer one twice as big.

"It's leaving many customers drinking more than they want to," said Lamb's fellow lawmaker, Greg Mulholland, who has called for a law requiring all venues to reinstate the smaller glass.

Jo Caddy, a 35-year-old account manager who cradled a large white wine at The Goose pub in central London, said smaller glasses hold far too little.

"I'd probably drink a bit quick and then I'd have to drink another one," she said.

Danny Blackmore, 31, manager of The Printer's Devil, another central London pub, said British culture, not glass size, is the problem. "You can serve them jugs or you can serve them thimbles -- if they're going out to get drunk they'll get drunk," he said.

Government research has found up to a quarter of adults are also consuming dangerous amounts of alcohol at home. Ministers said last year that middle-aged, middle-class professionals were the worst offenders.

Srabani Sen, chief executive of Alcohol Concern, a charity, said Britons simply have no idea how much they're drinking.

"The old rules of thumb have gone out of the window and part of that is down to the size of wine glasses," she said. "The glasses are larger and the wines are a lot stronger. It's a minefield for anyone trying to keep tabs on what they've had."

She said around 7 million Britons are regularly drinking above recommended limits — around two standard glasses for men and one-and-a-half for women.

Women are increasingly the ones breaching guidelines — often unaware of the potential health effects, which can include an increased risk of breast cancer, Sen said.

Britain's health department said it is so concerned that it is developing a $20 million education campaign to target adults later this year.

Prime Minister Gordon Brown, who is planning curbs on the sales of cheap alcohol in stores, has hinted he could scrap predecessor Tony Blair's decision to allow pubs to open 24 hours a day.

In a swank bar in London's legal district, Nick Sperrin, a 44-year-old client services manager, said most British venues now automatically serve wine in the largest glass available.

"People don't know how much they're drinking. There's a third of a bottle of wine in there," he said, pointing to his 8.4 ounce glass.

"They just say, 'Can I get a glass?' and they don't realize they're going to get a bucket."