Tube lines have been suspended after signal problems, Transport for London has confirmed.
Commuters were thrown into travel chaos on Monday evening after two lines were temporarily closed with major delays on four others.
TfL shut the Circle and Hammersmith and City lines due to signalling failures.
The District line is also almost entirely suspended with trains grounded between Richmond, Ealing Broadway and Upminster, Kensington Olympia and Earls Court, Wimbledon and Edgware Road.
Meanwhile, the Metropolitan line is also closed between Wembley Park and Aldgate, with severe delays on the rest on the line.
Severe delays were also reported on the Jubilee and Elizabeth lines.
Train staff would be accepting tickets on any other equivalent services, TfL said.
A TfL spokesperson said: “We apologise to customers this evening for the significant disruption to their journeys.
"This was caused by a signalling failure and engineers are working as quickly as possible to restore a normal service.”
London Buses as well as Southeastern, Greater Anglia and Thameslink trains are currently accepting tickets via any reasonable route.
The Tube chaos meanwhile resulted in a delayed kick-off for Fulham's London derby with Tottenham.
Both clubs pushed the 8pm kick-off on by 15 minutes as fans got caught in the delays.
TfL urged passengers to check the website or TfL Go app for further updates.
