Drivers on five London Tube lines have gone on strike on Friday – causing widespread problems.
Services on the Victoria, Central, Jubilee, Northern and Piccadilly lines are affected.
Transport for London (TfL) has warned people to expect “severe disruption”.
The strike began at 4:30am on Friday, and runs for 24 hours.
TfL said: “Stations will be open as usual, however, some tube lines will operate a much reduced service or no trains at all.”
Talks of the strike began because of disputes over pay and hours for drivers of the Night Tube, which was reopened after being suspended in March 2020 during the pandemic.