A 24-hour strike by Tube staff has had little impact on services, London Underground has claimed.
About 20 Tube stations were closed and all lines were open on Monday morning, as the strike continued.
Rail Maritime and Transport (RMT) union members who work at ticket offices and stations walked out at last night in a row over new rotas.
London Underground said a good service was running on most lines and denied RMT claims that it was running an “unsafe network”.
But an RMT spokesman described the situation as “chaotic” and claimed staff were working in positions they were not fully trained for.
Separate unofficial action has caused delays on the Northern Line after some drivers failed to turn up for work in support of a sacked colleague.
Tube staff previously walked out on New Year’s Eve.