Strikes on London Underground are due to cause major disruption, with most lines running a reduced service.
Transport for London says it will run as many services as possible on lines during the 48-hour strike, which will start at 9.30pm this evening and end on Friday morning.
Members of the RMT and TSSA unions are to strike in a row over plans to close ticket offices and introduce 24-hour services.
On the Victoria line there will be a service between Sisters and Victoria running approximately every five minutes in both directions, but trains will not stop at Warren Street station.
On the Piccadilly line there will be no service in central London but there will be trains running between Arnos Grove and Cockfosters around every ten minutes in both directions.
A normal service will operate on London Overground lines but some stations connected with underground stations will be affected.