The multiples have backed a government scheme designed to curb the sale of alcohol to under-age drinkers.

The scheme comes just hours before new licensing laws permitting supermarkets, bars and clubs to sell alcohol around the clock if they have applied to do so, come into force.

As part of the scheme, supermarkets will increase the number of signs in their stores encouraging people to carry proof-of-age identification, and increase the number of challenges to young customers to prove their age.

They will also work with the government to develop a national reward certificate for good performance in tackling under-age drinking. Supermarkets are also expected to set up their own schemes to reward staff.

The government has also promised that the police will make greater use of fixed penalty notices given to under-age drinkers who attempt to buy alcohol, and the time it takes the police to respond to calls from retailers will be closely monitored.

However, critics remain sceptical of the scheme. Shadow culture secretary, Theresa May, said: “No matter how many panicked initiatives the government announces, it will be the police and the public who will have to deal with the consequences of the government’s mistakes.”