Over 500 construction and maintenance workers on the London Underground could soon be out of a job, according to the RMT union.
Earlier this week, Transport for London completed the £310m takeover of contractor Tube Lines.
But RMT officials fear that this will lead to many of its members being axed, which resulted in a two-day strike last week. A further 48 hours of industrial action is planned during July.
General secretary Bob Crow said: “With TfL and the Mayor now taking control of the failed Tube Lines operation he has no excuse whatsoever for not intervening in the dispute over jobs and conditions which has left 535 out of 2915 staff facing the prospect of being thrown on the scrap heap.
“The simple fact is that the job cuts being cooked up would make it impossible for the Mayor and his officials to get the tube upgrade works back on track and would have dire implications for tube safety as essential maintenance works back up in the system.
“For too long Boris Johnson has tried to wash his hands of responsibility for the ongoing attacks on jobs and safety on London Underground and with today’s announcement on the Tube Lines takeover we are demanding that he steps up to the plate and starts sorting out the mess that has been left behind by the final collapse of PPP.”