Talks aimed at averting more strikes on London Underground in a dispute over jobs and ticket office closures will be held today.
Officials from the Rail, Maritime and Transport union and the Transport Salaried Staffs Association will meet LU under the chairmanship of the conciliation service Acas.
Members of the two unions staged a 24-hour strike last week which crippled Tube services, causing travel chaos.
The unions say a programme of hundreds of job cuts agreed by former London mayor Boris Johnson has gone too far and is affecting safety.
LU has agreed to new jobs but not enough to satisfy the unions.
The RMT has warned of further industrial action after February 6 if the row is not resolved.
RMT general secretary Mick Cash said: "RMT members on the London Underground stations see day in and day out the toxic impact of the job cuts programme and they are reporting back that it is horrific.
"It has now also been shown that at management level there is agreement with the union that the cuts have been a disastrous mistake and that the staff need to be put back on the stations.
"We now need a move away from the piecemeal and incremental approach to tackling this crisis and for LU to come forward with a serious package of proposals.
"With the constant overcrowding on stations and platforms it is only a matter of time before there is a major tragedy if we don't act decisively. Our dispute is about taking action to haul back the cuts machine and put safety back at the top of the agenda."