Commuters will face major travel issues as strike action is set to close many of central London’s tube stations on Sunday and Monday.
Up to 4,000 ticket and station staff are expected to walk out in a dispute of job losses and ticket office closures.
Transport for London (TfL) has warned some lines will have no service whatsoever and others will face significant disruption.
Here is everything you need to know:
When do they start and how long will they last?
Members of the Transport Salaried Staffs Association (TSSA) and the Rail, Maritime and Transport (RMT) union are due to strike from 6pm on Sunday.
The service will therefore be disrupted until the morning of Tuesday 10 January.
Why are the strikes taking place?
The walkout is in protest at 800 job cuts and the closure of ticket offices under former mayor Boris Johnson.
The unions are angry that current Mayor, Sadiq Khan, has not reopened any ticket offices.
Which lines are affected?
There will be no service on the Victoria and Waterloo & City lines. Piccadilly line services will still run between Hammersmith and Heathrow Terminals 1, 2 and 3, but will not go to Terminals 4 or 5.
Most Zone 1 stations will be shut and there will be no connections at major stations including Victoria, King’s Cross, Waterloo, Paddington, Euston, Bank and London Bridge.
Will there be alternative transport available?
Buses, DLR, London Overground and National Rail routes will be running but are expected to be much busier than usual.
TfL are set to deploy an extra 100 buses to deal with the extra demand.
How can I plan my journey? Are there any useful apps to get around?
You can use the TfL website to plan your journey or use City Mapper. Failing public transport you can hop on a "Boris bike" or use an Uber to get around the capital.
UK news in pictures
UK news in pictures
1/18 23 June 2017
British Prime Minister Theresa May addresses a news conference at the EU summit in Brussels, Belgium, June 23, 2017
2/18 22 June 2017
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Two women embrace in Borough Market, which officially re-opens today following the recent attack, in central London
Mayor of London Sadiq Khan attends the re-opening of Borough market in central London following the June 3 terror attack
People walk through Borough Market in central London following its re-opening after the June 3 terror attack
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Richard Arnold, Roy Larner, Piers Morgan and Susanna Reid on 'Good Morning Britain'
15/18 11 June 2017
England players celebrate after defeating Venezuela 1-0 to win the final of the FIFA U-20 World Cup Korea 2017 at Suwon World Cup Stadium in Suwon, South Korea
16/18 11 June 2017
England players celebrate with the trophy after the final match of the FIFA U-20 World Cup 2017 between Venezuela and England at Suwon World Cup Stadium in Suwon, South Korea
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Great Britain's Alistair Brownlee celebrates winning the Elite Men Columbia Threadneedle World Triathlon Leeds
Danny Lawson/PA Wire
18/18 11 June 2017
Two men drink beer outside the Southwark Tavern which reopened for business today next to an entrance to Borough Market which remains closed in London
How many more strikes will there be in 2017?
This depends on the outcome of negotiations between London Underground and union bosses.
The unions are looking for a “radically improved package” covering jobs and safety and have said no progress has been made as of yet.Reuse content