Chief operating officer Howard Collins told BBC Radio 4 that London Underground had already met some of Aslef's concerns.

BBC: Boxing Day Tube strike: Shoppers hit by delays

Howard Collins, London Underground's chief operating officer, said however he believed all such issues in the dispute "have been addressed".

BBC: Jubilee Line Tube drivers vote to go on strike

Howard Collins, London Underground's chief operating officer, criticised the union for demanding to be paid "twice for the same work".

BBC: Boxing Day Tube services disrupted by drivers' strike