A planned three-day strike by London Underground workers in a row over Tube ticket office closures has been called off after last-ditch talks.
Members of the Rail, Maritime and Transport union were due to walk out from 9pm, but a breakthrough was made at a meeting with LU.
The union said the industrial action had been suspended.
Acting general secretary Mick Cash said: "Due to the solidarity and determination of our LU members, and their delivery of rock-solid industrial action last week, we have been able to secure real movement and significant progress on the issues at the heart of this dispute in talks with the Tube management over the bank holiday weekend.
"Pre-conditions have been removed, protection of earnings has been agreed and we now have a viable framework for a proper review of the cuts and closures programme.
"As a result of that progress, secured directly through our members campaign of industrial action and the union's drive to get the facts across to the people of London, we are able to suspend the action due to commence this evening and further talks around the fundamental issues of cuts to jobs, services and safety will now take place."
The development followed talks at the conciliation service.
An Acas spokeman said: "We are pleased that we have been able to assist the parties to reach an understanding that allows the industrial action this week to be withdrawn."
Phil Hufton, chief operating officer of London Underground, said: "I am pleased that Londoners will not have to endure further strike action this week."
"The only way to resolve this dispute is for the RMT leadership to work with us to shape the future of the Tube in a changing world. It is good that they have committed to doing so alongside the three other unions involved.
"As we have always said, we are, of course, open to discuss any proposals our staff or the unions may offer.
"Modernisation of the Tube means that it is our intention to close all ticket offices, used in less than 3% of journeys, and instead deliver a vastly better customer service by bringing more staff than ever before out on to the concourses of stations at ticket machines, ticket gates and platforms - just as we delivered during the London 2012 Games.
"This will also allow us to save £50 million per annum to reinvest in better and more reliable train services and to keep fares down."
The Mayor of London, Boris Johnson, said: "This is a victory for common sense and for Londoners. The RMT leadership has finally seen that their tactics aren't working.
"I always said these strikes were pointless, and by getting so many people to work during last week's stoppage Transport for London has shown the RMT that its actions, supported by a minority of its members, will achieve nothing.
"It is vital that we continue to reform the Tube for the benefit of our passengers. I'm delighted that hard-working Londoners and businesses across the capital will now be free to go about their work without the threat of needless industrial action.
"It is essential we get on with our modernisation programme and that includes the closure of 260 ticket offices, saving £50 million a year that will be reinvested into the network. This will get more staff out from behind glass screens and back offices to help passengers, and all without any need for compulsory redundancies.
"There is no justification at all for holding London to ransom. Tomorrow the Government will announce their support for my proposals on ballot thresholds which will limit the power of unions to disrupt the capital in the future, on a whim and without majority support. That Government backing is very welcome, as is this morning's decision to call off the strike."