A 24-hour Tube strike will “definitely go ahead”, a union has said.
The announcement comes after London Underground (LU) made an increased but “final” pay offer in a bid to avert the action from 21:30 BST on Wednesday.
Unions were given until 18:30 BST to accept the offer which includes a 2% rise this year and £2,000 for drivers on the new night Tube.
Finn Brennan, a senior negotiator for Aslef, said unions were not being given enough time to consider the proposals.
Almost 20,000 workers are due to take part in the industrial action.
Aslef, the Rail, Maritime and Transport union (RMT), Transport Salaried Staffs Association (TSSA) and Unite have been in dispute over the pay offered for the new night Tube service, which is due to start at weekends from mid-September.
LU chief operating officer Steve Griffiths said in a message to staff that a “full and final” offer had been made in an attempt to conclude five months of talks.
Mr Griffiths said he had set a deadline so if industrial action was called off LU could plan to provide the “best possible service” to customers.
He added: “I have made this offer, as I firmly believe that providing you with certainty on your pay is the right thing to do.
“We are not asking staff to work unlimited nights and weekends. Most of you will not be affected at all by night Tube when it’s launched in September.”
LU’s latest offer included an average 2% increase on basic pay, RPI inflation or 1%, whichever is greater, in 2016 and 2017, a £500 non-consolidated “launch bonus” to all staff on night Tube lines or at stations serving these lines.
The strike will definitely go ahead – the company has said the offer is off the table” at 18:30 BST.
The RMT described the offer as “divisive and unacceptable” saying the union’s executive will be recommended to reject it.
General secretary Mick Cash 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 issues of work-life balance and the personal health and safety concerns are sidelined.”
The TSSA union also rejected the offer and urged LU to return to the negotiating table.
General secretary Manuel Cortes said: “This dispute is not just about pay but about how to run a safe and secure night Tube which serves the passengers as well as rewarding the staff.
“That service cannot be imposed top down. It has to be negotiated around the table with the staff who will be expected to deliver it.”