London's new mayor Boris Johnson announced Wednesday a ban on alcohol on the British capital's transport system, as part of a wider clampdown on crime and anti-social behaviour.

Conservative Johnson, who ousted long-time Labour mayor Ken Livingstone in elections last week which dealt a severe blow to Prime Minister Gordon Brown, said the booze ban would make life more pleasant for all Londoners.

"I'm determined to improve the safety and security of public transport in London and create a better environment for the millions of Londoners who rely on it," he said.

"I firmly believe that if we drive out so called minor crime then we will be able to get a firm grip on more serious crime."

The ban, which was a key pledge during his City Hall campaign, will outlaw drinking alcohol on the underground train system, trams, buses and the Docklands Light Railway from June 1.

But Bob Crow of the RTM transport union raised questions about the move — in particular warning of the risk of violence towards staff if they try to enforce the new rules with drunk passengers.

"We are in favour of any measure that will make our members' lives safer and curb anti-social behaviour, but it appears that this really hasn't been thought through very well and could well make matters worse," he said.

"Perhaps the mayor will come out with his underpants on over his trousers like Superman one Saturday to show us how it should be done," he added.

Johnson, a former journalist ridiculed by critics as a political buffoon who can't take anything seriously, swept to office last week in the most high-profile defeat for Brown's Labour party as it suffered its worst local election results in 40 years.

AFP