Talks have restarted between management and the Tube unions over the new Night Tube service as London faces another set of 24-hour strikes on 8 and 10 September 2015. The unions were bouyed after London Underground (LU) last week (27 August 2015) announced the cancellation of its 12 September launch date for the Night Tube – a move that Boris Johnson blamed on "Corbyn-mania". The Mayor of London claimed that the TSSA, Unite and RMT unions were gripped by Jeremy Corbyn's popularity, with Johnson telling LBC Radio this morning that their protest over pay and work conditions was political.

But despite the top Tory's remarks, a TSSA spokesperson told IBTimes UK that there was positive sentiment around the talks as the parties meet at mitigation service Acas today. "However, there are a number of key issues still to be addressed in talks, including some serious concerns that we have around health and safety in relation to Night Tube," the spokesperson added. "TSSA has consistently supported the introduction of Night Tube but argued that the predetermined September deadline for its introduction was wholly unrealistic given the various safety issues that would need to be resolved in discussions that had not started in earnest before the summer."

Transport for London (TfL) has said it still expects the Night Tube, which will run on major lines over weekends and is expected to support 2,000 jobs, to launch in the autumn of this year. Nick Brown, managing director of LU, has said: "Our objective is to reach an agreement that ends this dispute and delivers the Night Tube for Londoners this autumn."

But the exact launch date will be dependent on how the negotiations at Acas go. A union source close to the talks told IBTimes UK that he is sceptical of an autumn roll-out, claiming it would be unlikely for the service to be running before Christmas.

Meanwhile, the RMT has threatened to call further industrial action if LU run any Night Tube test trains. A circular to the union's Underground branch added: "Likewise, if our reasonable and just demands to protect the jobs and terms and conditions of station staff are not met, this will also lead to us calling further industrial action without delay."