A walkout by Tube drivers is causing Boxing Day travel misery in the capital as strike action cripples London Underground (LU).
Underground drivers belonging to the union Aslef are staging a 24-hour strike over the union's demand for extra pay for its members working on the public holiday.
Last week a High Court judge concluded that the strike was lawful and could go ahead following a legal challenge by LU.
Services on the Circle, Central, Hammersmith & City lines have been suspended due to the strike, with most other lines running reduced services.
Aslef general secretary Mick Whelan said the demands for extra pay and voluntary working on Boxing Day were "negotiable".
He told BBC Radio 4's Today programme: "My team that has been in there for the best part of two years has offered various solutions that would underwrite or part underwrite what we are seeking to achieve.
"There's various transfer and training agreements within the company that if we changed them would subsidise what we are seeking to achieve.
"The original dispute two years ago was about quality time off.
"We agree that we made an agreement with the company in the mid-90s. At that time very few trains ran on Boxing Day. In the last decade and a half we have run as many trains on Boxing Day some years as we run on any day of the week so the intended quality time people were expecting to get has never happened."
Whelan said the union had "no intention" of staging a strike during the Olympics.
Howard Collins, London Underground's chief operating officer, told the Today programme the number of drivers scheduled to work this year had been reduced from last year's 1,100 to 880.
He added: "I can't pay people twice. The salary for train drivers, including working Christmas Day and Boxing Day, is an all inclusive salary."
The Piccadilly line is only operating between Heathrow Terminal 5 and Acton Town, and between Arnos Grove and Cockfosters.
Special services are operating on the Jubilee line between Stanmore and Finchley Road, but there are no trains running on the rest of the line.
The Metropolitan line is suspended between Wembley Park and Uxbridge/Amersham/Chesham and Watford, and between Baker Street and Aldgate. A reduced service is operating between Wembley Park and Baker Street.
The Bakerloo line has no service between Paddington and Elephant & Castle due to strike action, with a reduced service on the rest of the line.
On the District line there are no trains running between Parsons Green and Wimbledon or Earl's Court and Kensington Olympia.
The Northern line is running special services between Stockwell and Morden, and between Edgware and Golders Green, but there are no trains on the rest of the line. Replacement buses are operating between Euston and High Barnet/Mill Hill East.
There is a special service running throughout the Victoria line.
The Waterloo & City line is not operating due to a planned closure, and there is no service between Bank/Tower Gateway and Poplar/West India Quay on the DLR because of planned engineering works.
On the Overground there is no service between Gospel Oak and Barking, Highbury & Islington and West Croydon, Euston and Watford Junction, Richmond and Stratford, and Clapham Junction and Willesden Junction due to planned closures.