London Underground is taking legal action in a bid to prevent a Boxing Day strike by Tube drivers going ahead, it was announced today.
Members of the drivers' union Aslef are due to stage a 24-hour walkout on Sunday over a claim for triple pay and a day off in lieu.
Transport for London said it had asked the union to withdraw their action otherwise LU will go to court this afternoon.
A spokesman said : "LU is currently seeking an injunction to prevent the potentially disruptive and completely unnecessary strike action called by the leadership of the Aslef union. The union has unilaterally ripped up a long-standing agreement on pay and working hours that gave LU employees increased pay and 6.8 weeks holiday in return for working some bank holidays, including Boxing Day.
"We have tried to resolve this dispute through negotiation, but our offer to reduce the number of drivers rostered to work on Boxing Day was flatly rejected and union representatives walked out of talks at Acas. This left us no option but to seek a legal solution".
Meanwhile London's Mayor today called for an end to "divisive and pointless" industrial action by transport workers in 2011 in a festive message which also praised staff for their efforts this year.
Boris Johnson praised the work of Transport for London employees to keep bus, train and Tube services running during the recent cold weather and hailed ongoing investment in the capital's transport system.
But he also urged staff to work together in 2011 to deliver improvements and end the "fruitless confrontation and disruption" caused by "pointless" industrial action.
Members of the Rail Maritime and Transport union and the Transport Salaried Staffs Association have staged a series of strikes this year over job losses and are threatening further walkouts in the New Year, while members of Aslef are planning to strike on Boxing Day.
"I really don't think that when we have so much to do, when we have so much to look forward to, that we will achieve anything more by pointless industrial action.
"All it succeeds in doing is alienating Londoners, stopping people from going about their jobs, impeding our great city from leading the country, as it will, out of an economic recession.
"We have a fantastic opportunity to harness investment in London transport. People are looking to us to provide ever better services. I believe that we are providing ever better services, in spite of some pretty challenging meteorological conditions," he said.