Tube lines are set to be disrupted next week as two unions plan a strike.

The RMT and TSSA unions will stage a 24-hour walkout as they dispute pay and condition for the new night tube which is due to start at weekends from September 12 on Central, Jubilee, Northern, Piccadilly and Victoria lines.

RMT general secretary Mick Cash said: "The industrial relations situation on the Tube has sunk to an almost unprecedented low with all four unions united and balloting for action over pay and working arrangements due to be ushered in under the guise of the mayor's 'night Tube' vanity project in just 10 weeks' time."

TSSA general secretary Manuel Cortes said: "We hope that this result will show Boris Johnson just how angry our members are at his plans to try and rush the start of the night Tube without any detailed agreement on manning levels."

The walkout will take place on Wednesday, July 8.