London's new mayor Boris Johnson announced yesterday that alcohol would be banned on the capital's transport system from next month.

The ban on drinking from or carrying open alcohol containers was a key manifesto pledge of Mr Johnson, the irreverent journalist-turned MP who defeated incumbent Ken Livingstone in a closely fought election last week.

The ban, which will apply to buses, underground trains, trams and stations, will come into force on June 1.

"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," Mr Johnson 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."

Tackling crime, particularly serious violence among young people, was one of the main planks of Johnson's election campaign and he has already vowed to put it at the forefront of his supporters.

Posters informing travellers of the ban will now go on display.

"Public drinking and the behaviour sometimes associated with it can, and does, deeply affect people's ability to enjoy public spaces," said Don Shenker, chief executive officer of Alcohol Concern.

"Taking a firm approach to public drinking in this way sends a strong message that public drunkenness is socially unacceptable and will support both the public and transport staff."