Last ditch talks aimed at averting a strike by London Underground workers will be held today, with little sign of the action being called off.
Members of the Transport Salaried Staffs Association (TSSA) and the Rail, Maritime and Transport (RMT) union are due to walk out for 24 hours from 6pm on Sunday, causing travel chaos for millions of passengers.
Talks over staffing and ticket office closures collapsed on Friday but the TSSA made a surprise announcement that another meeting will be held at the conciliation service Acas.
Transport for London has advised passengers that there will be a severely reduced service across the Tube network on Sunday evening and all day on Monday if the strike goes ahead.
Steve Griffiths, chief operating officer for London Underground, said: "There is no need to strike. We had always intended to review staffing levels and have had constructive discussions with the unions. We agree that we need more staff in our stations and have already started to recruit 150 extra staff.
"This number is bound to increase as we work through the other areas that need to be addressed. Taking into account existing vacancies and natural turnover this means that around 500 staff will be recruited for stations this year. There will also be increased opportunities for promotion.
"All of this will ensure that our customers feel safe, fully supported and able to access the right assistance in our stations at all times. We encourage the unions to continue working with us on this process and we are available for talks at all times through the weekend in order to resolve this dispute."
The Mayor of London, Sadiq Khan, said: "This strike is unnecessary and I urge the unions to call it off immediately.
"A lot of progress has been made and there is a good deal on the table. I strongly urge the unions to call off this strike which will cause misery and disruption to millions of Londoners.
"I have instructed TfL to work around the clock throughout the weekend to continue negotiating to resolve this dispute. There is no reason for the unions to strike.
"I can assure Londoners that we will continue to do everything we can to avert this strike."
TfL said it will try to run as many services as possible, but travellers are advised to complete their journeys by 6pm on Sunday, and that most Zone 1 stations are likely to be closed throughout the action.
National Rail services will not be affected by the strike but there will be no underground services from busy interchange stations such as Victoria, King's Cross, Waterloo, Paddington, Euston, Bank and London Bridge.
Piccadilly line services will still run between Hammersmith and Heathrow Terminals 1, 2 and 3, but there will be no service to Terminals 4 or 5.
There will be no service on the Victoria or Waterloo & City lines, and all other lines will be severely affected with limited services in outer London.