A power outage has hit multiple rail networks across the capital, causing widespread cancellations and delays of up to 60 minutes across services, according to National Rail.
The outage, which was first reported at around 4.33pm, is affecting electric traction trains and causing “major disruption”.
The affected services include those operated by Avanti West Coast, c2c, the Elizabeth line, Greater Anglia, the Stansted Express, London Northwestern Railway, London Overground, and West Midlands Railway.
National Rail said: “There was a power outage earlier today which has caused disruption to some routes across London and the Midlands.
“Services are now on the move, but may still be severely impacted.”
Delays and disruption are expected until the end of the day, with some routes still cancelled or revised as services recover.
Passengers are being urged to check their journeys before travelling.
The Elizabeth line has advised passengers that tickets will be accepted at no extra cost on several alternative routes, including South Western Railway between London Waterloo and Reading, London Overground, London Underground, Docklands Light Railway, Southeastern between Abbey Wood and London terminals, Thameslink between Abbey Wood and Farringdon, and Great Western Railway.
Greater Anglia and Stansted Express passengers can use their tickets on c2c between London Fenchurch Street and Southend Central, the Underground, and on Great Northern and Thameslink services between London and Cambridge or Hertford North.
London Overground passengers are permitted to use London bus services at no additional cost via any reasonable route.
The disruption is believed to have been caused by a “nationwide power fluctuation” with National Grid, which led to temporary power loss on parts of the rail network.
National Rail is directing passengers to use its real-time Journey Planner or new live map to check the status of trains and find alternative options.
Anyone delayed as a result of the disruption could be entitled to compensation and should keep their train ticket and journey details to support any potential claim.