RMT General Secretary Mick Cash said:
"The ACAS talks, which RMT had been calling for with the objective of reaching a fair and just settlement in this case, have broken down due to a total refusal of the management side to engage in any kind of meaningful discussions. As a result of London Underground's disregard for negotiations and their own procedures Mondays action goes ahead as planned.
“RMT has been pointing out for some time now that a new culture of harassment and misuse of procedures is rife on London Underground at the moment and the union will not stand back while individuals are fitted-up and picked off as has happened in this particular case on the Northern Line.
“The unattributed briefings to the media that our member had been sacked for “drinking on duty” are totally untrue. Those smears have been repeated by the Transport Commissioner and the union has now taken that matter up with him directly.
"Our member has a specific medical condition and the union maintains that it was the failure to follow agreed procedures, and to recognise that condition, that has led to this unwarranted dismissal and the subsequent strike action. "