Supermarkets and petrol stations that decide to sell alcohol 24 hours a day will fuel a rise in alcohol-related violence, magistrates have warned.

From November changes to the alcohol licensing laws will mean that pubs, clubs, bars and shops will be able to apply to extend their licenses or serve alcohol around the clock.

However, Rachel Lipscomb, chairman of the Magistrates’ Association, which represents 30,000 justices of the peace in England and Wales, has warned that these changes will increase violence.

She said: “The present situation is already bad. There is a lot of drink-related crime which ranges from domestic violence and assaults resulting from altercations in or outside pubs to public order offences.”

C-stores and petrol stations that extend their licensing hours, she added, would be the most vulnerable. “If a group of drunk youths comes in late at night, will they feel strong enough to turn them down?”

John Howson, an Oxford magistrate, added: “If you can buy alcohol at three in the morning and that tips you over the edge, where without the extra drink you might not have been, then you could get more crime.”