Riders of the London Underground will hold cocktail parties inside rear cars of subway lines at 9 p.m. on Saturday to mark the end of Britons' drinking tradition on public transports.

Drinking, and drunkenness, will be banned on trains and buses starting June 1 for a safer and more pleasant travel, a regulation introduced by new London Mayor Boris Johnson on May 7.

A co-organizer of the Final Circle Line Party has so far received confirmation from more than 9,000 guests through two Facebook web sites announcing the event. The Circle Line, one of the lines of the London Underground, has 27 stations.

"Revelers should bring their own cocktails," James Darling, 20, a Web site designer helping set the Circle Line event, told Bloomberg.com in a phone interview.

The London Underground is allowing the party but advised revelers to drink responsibly. London police will be present to guard against trouble.