Northern Line Tube drivers strike over sacking
Tube drivers on part of London Underground (LU) are striking over the dismissal of a colleague.
RMT union members on the Northern Line walked out at 04:30 GMT for 24 hours.
Phil Hufton, from LU, said it was operating a "good service" and the RMT had "absolutely no basis" to strike after their member was dismissed for "failing an alcohol breath test".
But RMT general secretary Mick Cash dismissed the claim that alcohol was involved as "totally untrue".
Mr Cash from the Rail, Maritime and Transport (RMT) union said the driver had a "specific medical condition" and LU had failed to follow procedures which had "led to this unwarranted dismissal and the subsequent strike action".
According to LU the strike received little support from RMT members.
Mr Hufton said: "The strike has been poorly supported and our staff have come to work to help Londoners get to where they need to go."
The conciliation service Acas held talks on Friday in an attempt to avert the strike action but these broke down.