The government is to ban the sale of ultra-cheap alcohol in England and Wales, the Home Office has announced.

Ministers hope the move, which will come into force on 6 April, will stop the worst instances of deep discounting, which has resulted in cans of lager being sold more cheaply than water in supermarkets.

An official impact assessment says that the ban on sales of alcohol at below cost, defined as duty plus VAT, will mean an ordinary 440ml can of beer or lager cannot be sold below 50p.

The new "floor price" for a bottle of wine will be £2.24; a bottle of vodka or other spirits will cost a minimum of £10.16.

Low-strength beers which have an alcoholic content of 1.2% or less will be exempt from the policy as will duty-free sales on ships, aircraft and in airports.

They also point to growing evidence of "pre-loading" with two-thirds of young people who were arrested for alcohol-related crime and disorder in one English city admitting to have "tanked up" with cheap supermarket booze before going out.