A 24-hour strike by thousands of London Underground workers will go ahead from Sunday evening after hopes of a peace deal over job losses collapsed today.
The Rail Maritime and Transport union (RMT) and the Transport Salaried Staffs Association (TSSA) said their members will walk out at 6.30pm on Sunday, threatening travel chaos for commuters and other passengers.
It will be the fourth 24-hour stoppage in recent weeks in a worsening row over 800 job losses in ticket offices.
Talks at the conciliation service Acas ended last night without a breakthrough and union leaders said today they had effectively broken down, ending any hopes of a last minute deal.
London's mayor and Transport for London (TfL) set out a range of transport measures that will supplement Tube services to help people travel around the capital, including 100 extra buses and capacity for around 10,000 more journeys on the River Thames.
London Underground (LU) said it ran 40% of its normal services during the strike on November 3, rising to 50% for large parts of the day, carrying around half its normal passenger numbers.
RMT general secretary Bob Crow accused the company of "intransigence" after the union offered to suspend industrial action if management agreed to review the job cuts and their impact on stations.
He said there were fresh delays on the Circle and District lines this morning, adding: "The unprecedented and continuing chaos on the Tube has hit services again as the combined impact of maintenance cuts and failing infrastructure is rammed home.
"This daily crisis will only get worse unless there is an immediate halt to the cuts programme and urgent top-level talks with the unions to map a way forward from this chaos."
The TSSA detailed a list of 10 incidents where it claimed Tube trains stopped at closed stations during strikes and wrongly allowed passengers to "wander off" before the driver realised he should have kept the carriage doors shut.
The worst incident was at Canada Water during the second strike on October 4 when the union claimed that up to 40 passengers found themselves locked in the station for 40 minutes after leaving their Tube train which should not have stopped.
They eventually found a stairway that led up to the local bus garage, said TSSA.
"We are very concerned about the safety implications of passengers being left stranded at locked and unmanned stations," said general secretary Gerry Doherty.
"We are highlighting the problem today because we do not want to see any repetition of those incidents during Monday's walkout.
"It is high time that the mayor got a firm grip on which stations are open and which stations are closed during the strikes.
"We have given him enough notice of these walkouts, which allows him to run a limited service with passengers being told quite clearly which stations are closed and where passengers should clearly not be allowed to exit those trains."
TfL said it "condemned" the leaderships of the TSSA and RMT, saying they had "scuppered" productive talks and walked away from an offer of a further six weeks to review its staffing plans.
Howard Collins, chief operating officer of LU, said: "We have been consulting with the union leaderships for six whole months to try to establish what specific safety concerns they may have. We yesterday offered a further six weeks to discuss our plans and to see if there are any local issues which need to be addressed. Despite this offer, the leaders of the TSSA and RMT have demonstrated once again that their only interest is in disrupting Londoners - despite the fact that over half of the post reductions have already been achieved through voluntary redundancy and natural wastage.
"If they are serious about resolving this issue, they should call off their totally unnecessary strike immediately. We will talk to them right now on any genuine safety issues they have. We want an end to this dispute and believe that a resolution will be only achieved through talks, not by further threats to disrupt London."
Mayor Boris Johnson, said: "I feel sure that the defiance and contempt Londoners have shown for the previous futile strike action will be evident once more. The leaderships of the TSSA and RMT may well cause inconvenience through their stubborn refusal to face facts, but we are determined to keep the capital moving by all means available to us. London will not be beaten."
Transport Commissioner Peter Hendy said: "London Underground has been ready and willing to discuss any safety concerns which the RMT and TSSA leaderships may have had since these proposals were announced at the start of March. We remain willing to discuss these at any time.
"The fact is that the TSSA and RMT leaderships are not facing reality, and are determined to inconvenience Londoners by striking over post reductions, many of which have already happened.
"More than half of the 800 post reductions have been achieved - 150 management and administrative staff have taken voluntary severance, and 300 vacant stations posts will not be filled. When it is introduced in February the new LU staffing structure will mean every station will continue to be staffed and every station with a ticket office now will still have one. The Tube's excellent safety standards will be maintained and not one member of staff will have faced compulsory redundancy."
Katja Hall, CBI director of employment policy, said: "It is disappointing that this dispute could not be resolved at Acas, which means that Londoners will suffer travel disruption for the fourth time in as many months.
"This is a big disruption caused by a small union minority. As the law stands, strikes are often decided by a tiny turnout of the workforce. In this case, just 33% of balloted members supported the strike, only 17% of the total London Underground workforce.
"The CBI is calling for changes to the law to ensure that strikes can only go ahead if 40% of those balloted, as well as a simple majority of those voting, support the action."