London Underground chiefs and union bosses are in talks to avert a 24-hour tube strike planned for tomorrow.
There are four unions involved who represent 20,000 workers expected to take part in the industrial action.
The strike is due to start tomorrow (Wednesday 7) at 18:30, which will mean no tube services at all from tomorrow evening and all day Thursday.
The potential strike action is over the introduction of a new night tube service, which is due to start at weekends from mid-September on parts of the Central, Jubilee, Northern, Piccadilly and Victoria lines.
The Rail, Maritime and Transport union (RMT), Transport Salaried Staffs Association (TSSA), Unite and ASLEF unions rejected the latest pay offer from London Underground on Monday.
The offer included an average 2 per cent increase on basic pay, and a £500 non-consolidated "launch bonus" to all staff on night Tube lines or at stations serving those lines.
Transport bosses also offered a £2,000 "transition bonus" for drivers working on the overnight services.
Previously a 0.75% pay increase with an additional payment of £250 for drivers was offered.
Mick Cash, leader of the RMT, the largest of the unions, said: “While a small minority of staff are being offered a non-consolidated one-off lump sum the remainder of staff are ignored and the key issue of work/life balance and the personal health and safety are side lined.”
Finn Brennan of Aslef, which represents the majority of train drivers, added: “LU’s behaviour is bizarre – this was not a serious offer. They realised it would not be possible for us to accept their ultimatum. We have waited three months and then they give us just four hours to accept. This is not serious negotiation.”
London Underground's chief operating officer Steve Griffiths said: "Our customers are advised to check the TFL website for the latest information as we seek to resolve the dispute and to keep London moving should the unions go ahead with their action.
"We are available for talks at Acas all day."
He added: "Londoners and businesses overwhelmingly back the night Tube. It will make life better for everyone, cut journey times, create jobs and boost the economy. Many of our staff will not be affected by the new services as we are operating Friday and Saturday night services on five lines."