Howard Collins, London Underground's chief operating officer, said before the strike dates were announced: "We have been in discussions with the Aslef leadership to find a way to end this dispute and we made what we believed was a very fair offer.
"Unfortunately, this was not accepted and the offer has now been withdrawn so that further options to resolve the issue can be explored with the union at Acas today.
"LU has a long-standing agreement with all trade unions which covers working arrangements on Bank Holidays, including Boxing Day.
"However, we have shown good faith and tried to find ways forward.
"Further industrial action will not achieve anything and I would urge Aslef leadership to work with us to resolve this dispute."
More top news
Two police officers helping to guard diplomats have been sacked for sharing pornographic images on their mobile phones.
A 32-year old man from Hampton has been jailed for five years historic sexual assaults in the late 1990s.
A teenager who was mistakenly released from prison after he was arrested on suspicion of attempted murder has been detained by police.