A train drivers’ union is set to ballot its members on whether to strike on Boxing Day for the third year running.

Drivers staged walk outs on December 26 in 2010 and 2011 following a row over additional pay.

London Underground (LU) has offered what it says are more flexible working arrangements for drivers on the bank holiday this year to end the long-running dispute.

But the union’s general secretary Mick Whelan described the latest offer as “a step backwards” and said members would continue to demand higher wages for working the public holiday.

He said: “This offer is enormously complex and offers nothing that hasn’t been offered before. It is tremendously disappointing that they still haven’t come up with anything our drivers consider even half reasonable.

“It is not an encouraging start to the prospect of a strike again this year but there is still time and we’re hoping to get an agreed settlement.”

ASLEF is also pressuring LU to make working the bank holiday optional and claims there would be plenty of drivers willing to take the shift for additional pay.

LU's chief operating officer Howard Collins earlier described the offer as “very fair” and claimed the train operator had shown “good faith in trying to find a way forward”.