Commuters have been told not to travel this morning after a major signalling problem at London Waterloo.
South Western Railway said due to the failure of the equipment at the station, it could not "use platforms 1 to 14 at this time, significantly limiting capacity".
The company has apologised for the disruption and told customers to check for updates, while National Rail has also warned that "major disruption is expected until the end of the day".
SWR added: "Engineers are on site attempting to restore the use of the platforms, but with very few trains able to move in and out of London Waterloo and trains and crew already displaced, services across the network are severely disrupted.
"While we are hoping to restore some services later in the day, these are still likely to be subject to delays and alterations."
At 10.15am, SWR said the issue had been fixed, but added it is still advising commuters not to travel.
"With so many trains and their crews out of position," it added, "only a limited number of training services will be reintroduced over the coming hours" ahead of the afternoon and evening peak.
According to the Office of Rail and Road, London Waterloo was the fourth busiest train station in the UK last year, with an estimated 62.5 million entries and exits in 2023/24.
Passengers have been told that they will not be able to claim a taxi ride from SWR, but were told unused tickets bought today will also be valid on Tuesday "due to the level of disruption".
Read more from Sky News:
Key recommendations from report into 'broken' water industry
Paul Gascoigne taken to hospital after collapse at home - reports
Tickets for disrupted services will be accepted at no additional cost on CrossCountry services between Reading and Bournemouth, Southern trains between Victoria, Portsmouth Harbour and Southampton Central, and Great Western Railway journeys between Salisbury, Westbury and Weymouth.
Commuters can also use their tickets on London bus routes between Waterloo and Zone 6 areas, as well as some Falcon Buses, Stagecoach and Morebus services.
(c) Sky News 2025: 'Do not travel warning' issued as London Waterloo station hit by 'major signalling failure'
Compulsory water meters and regulator abolished - key recommendations from landmark report into 'broken' water industry
Body found in search for Rachel Booth who was last seen at a petrol station
Government to conduct review into state pension age
Driver who inhaled laughing gas before killing 81-year-old cyclist in hit-and-run detained
Woman who killed her baby by violently shaking her jailed
Former Conservative MP Katie Wallis appears in court accused of having false passport
£104bn of water industry investment will come from bill payers, environment secretary concedes
Paul Gascoigne: Former England footballer taken to hospital after collapse at home - reports
Divers discover Royal Navy warship HMS Nottingham 110 years after it was lost in action
