London Underground drivers on two lines are to stage a 24-hour strike from tonight over claims that industrial relations have broken down.
Members of the Rail, Maritime and Transport (RMT) union working on the Hammersmith & City and Circle lines will walk out at 9.30pm.
The union accused management of being "heavy handed", including putting staff toilet breaks on a stopwatch, and a "flagrant disregard" for agreed policies and procedures.
RMT general secretary Mick Cash said: "This dispute is about the basic issues of protecting working conditions of our members and defending agreements from attempts to drive a coach and horses through them."
Sorry for everyone affected by the Tube Strike...so sad we can't get back the Spirit of the Olympic Games 2012...everyone was so friendly.
-- ((( Peace ! ))) (@banksger1) September 15, 2016
Transport for London said there will be no Hammersmith & City line service and a very limited service on the Circle line from around 9pm and all day Friday.
Steve White, operations director for London Underground, advised passengers to check travel information.
He said: "All other Tube lines and other TfL services will be operating as normal and we'll be making sure that everyone has the information they need to re-plan their journeys if necessary."