A 24-hour strike by London tube train drives will go ahead from early Monday morning.
The main impact is likely to be upon commuters who would normally use the Northern Line.
Talks between the RMT union and Transport for London at ACAS (Advisory, Conciliation and Arbitration Service) broke down on Saturday evening. The RMT has blamed TfL's management for failure of the talks. The issue is the sacking of an RMT member.
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.
"The unattributed briefings to the media that our member had been sacked for 'drinking on duty' are totally untrue.
"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."
The strike's impact is likely to be limited.
TfL says: "We will try to run a good service on the Northern Line but there may be some disruption. Other Tube services, the DLR, London Overground and National Rail will operate normally."
Stations will be open as normal: "Station staff will be available across the network to help customers with their journeys. We advise you to plan ahead and allow extra time for your journey."