Talks which could prevent a strike by Tube signal workers on New Year's Eve have ended without an agreement.
About 330 Rail, Maritime and Transport (RMT) union members are being balloted on whether to strike in a row over pay, hours and potential job cuts.
The ballot is due to be held next week and the time frame means industrial action could fall on 31 December.
Aslef members have already voted to strike on 24 December and 5 January over the demotion of a driver.
Bob Crow, general secretary of the RMT said: "We made it quite clear to London Underground that longer shifts, shorter rest breaks and a cull of 76 jobs as well as other strings were completely unacceptable in what is a key
"Unfortunately the company would not negotiate and as a result we are still in dispute."
A London Underground spokesman said: "The RMT has balloted for strike action and withdrawn from negotiations before the agreed procedure has been concluded.
"The deal on offer is a generous one. Nobody will lose their job or lose out financially."
Further talks are planned next week, said the company, adding that strike action would not resolve the issue.
Tube drivers on the Piccadilly line are to strike on Christmas Eve and 5 January in a row over the demotion of a driver for passing red signal lights.
Train drivers' union Aslef accused LU of unfair treatment of the driver.
Staff at the Acton Town depot of the District line voted to strike on 4 January in protest at "appalling facilities" at Earl's Court station.