Alcohol may soon be sold around the clock at supermarkets, under changes to licensing laws in England and Wales which come into force in November.
It may soon be possible to buy alcohol around the clock
The big three supermarkets - Tesco, Asda and Sainsbury's - have applied for 24-hour licences at a combined total of 435 outlets.
Pressure group Alcohol Concern said it feared the move could see an increase in problem drinking.
But the supermarkets said their staff were trained to ask for proof of age.
In addition, workers would continue to refuse to sell alcohol to people who were already under the influence, regardless of their age, they said.
The new licensing laws which start in November give any licensed premises - be it pub, club, restaurant, off licence or supermarket - the right to apply for 24-hour or extended opening hours.
Approximately 130,000 such businesses are expected to apply, according to the Department of Culture, Media and Sport (DCMS).
Tesco wants 24-hour alcohol licences for 300 stores, and extended licences for another 200; while Asda has applied for 24-hour licences at 110 outlets, and wishes to gain extensions for another two.
Sainsbury's said it wanted 24-hour licences for its 25 stores that open around the clock, and that 500 outlets had applied for an extension.
But Alcohol Concern said that supermarkets needed to go beyond simply sticking to age restrictions and prohibitions on sales to the intoxicated if they were not to exacerbate Britain's problems with problem and binge drinking.
"If supermarkets are to sell alcohol round the clock, they need to step up to the challenge of responsible practice, and that means a commitment not to run irresponsible cheap drink promotions that encourage people to drink too much, and no sales to people who are underage or obviously drunk," said an Alcohol Concern spokeswoman.
A Tesco spokesman said the chance to increase the hours in which its stores sold alcohol was all about extra convenience for its customers.
"Customers tell us they want to be able to buy alcohol as part of their weekly shop, whatever time of the day they choose to do their shopping," he said.
Morrisons, Somerfield and Marks & Spencer have not applied for any extensions to their alcohol licences.