London Underground workers are to stage four strikes, including one on Boxing Day, in a row over bank holiday pay, it was announced today.
Aslef said its Tube members will walk out for 24 hours on December 26, January 16 and February 3 and 13 after failing to agree payments for working on Boxing Day.
Around 2,200 Aslef members were balloted, with 92% of those who voted backing a campaign of industrial action.
The union has been seeking "adequate compensation" for working on Boxing Day, saying they had been offered no extra pay.
Aslef said it also wanted Tube drivers to be able to volunteer to work on such an "unsociable" day.
London Underground (LU) called on Aslef to abandon the strikes, saying its "outrageous" claim for triple pay and a day off in lieu for working Boxing Day went against an agreement all unions were signed up to.
The company said Aslef and other unions had signed up to an agreement covering operational staff, which saw them getting higher salaries and increased annual leave on the understanding that this would involve working on some public holidays.
"The agreement, which specifies that overtime is only paid for unrostered work or for work attracting a higher salary, is once again being ignored by Aslef's leaders," said LU.
The company said it had reviewed the level of service for Boxing Day to match customer demand and as a result has reduced the number of train staff required to pre-2010 levels, so only a quarter of the Tube's 3,500 drivers are needed to run the service.
"The Aslef leadership has called the strike action despite the fact that only around 42% of those balloted voted in favour of strike action," said LU.
Howard Collins, LU's chief operating officer, said: "It is disgraceful for the Aslef leadership to threaten strike action while we are engaged in continuing discussions on this issue. The threat of strike action will not achieve anything and I urge Aslef to join us in our commitment to resolve this matter through discussions.
"LU has a long-standing agreement with all of its trade unions which cover staff working arrangements on bank holidays, and Boxing Day is included in that agreement.
"However, we have shown good faith in reviewing Boxing Day services so that staffing requirements are lower than when Aslef raised this matter last year, and Aslef should do the same."
Colin Stanbridge, chief executive of the London Chamber of Commerce and Industry, said: "It is completely unreasonable of Aslef to hold London and its businesses to ransom through yet more Tube strikes. Retailers have already had one of their toughest years with recent sales figures showing a decline year on year fuelled by poor consumer confidence, rising unemployment and mild weather.
"The last thing they need now is disruption on Boxing Day, one of their most important trading dates. We urge Aslef to consider the damage their actions will cause to the London economy and reconsider their decision."