Dec. 23 (Bloomberg) -- Workers on London's subway will strike over pay and working conditions on Dec. 31, jeopardizing Mayor Ken Livingstone's plan to offer free public transportation for people returning from New Year celebrations.

Members of the National Union of Rail, Maritime & Transport Workers will hold a 24-hour strike on beginning at noon local time New Year's Eve, Bob Crow, the union's general secretary, told reporters outside the RMT's London headquarters.

A 24-hour strike also will halt the system beginning at 9 p.m. Jan. 3, Crow said. The union set a deadline of 3 p.m. today for London Underground Ltd. to meet the demands of the 300 workers involved. The two sides are taking part in talks today aimed at resolving differences concerning the system, also known as ``the Tube.''

``Unless significant progress is made at today's talks, our signals and line-control members will strike for 24 hours on New Year's Eve and again on Jan. 4,'' Crow said. ``These people have the ability to shut down the whole Tube.''

Commuters using the subway's Piccadilly Line, which links north and central London with Heathrow Airport, will suffer disruption and delays tomorrow when workers on the route walk out on strike. The action by workers represented by the Associated Society of Locomotive Engineers and Firemen is in protest at the downgrading of a driver who passed four danger signals.

To contact the reporter on this story: Claire Shoesmith in London at cshoesmith@bloomberg.net.

Last Updated: December 23, 2004 06:25 EST