Commuters are being warned to brace themselves for rush hour rail chaos following a major signal failure at Victoria station.
Main line train operators warned that disruption would last the entire day due to the seriousness of the fault.
A spokesman for Network Rail said seven of the station’s 19 platforms will be closed for the entire day.
The platforms affected are numbers nine to 15.
It means Southern and Gatwick Express services into and out of London will be hit with a day of severe delays and cancellations.
Southern Rail tweeted: “Due to signal failure between Victoria and Clapham junction, some London bound lines are blocked. There is ticket acceptance in place.”
London Victoria is the UK’s second busiest railway station with more than 80 million passengers passing through a year.
A Network Rail spokesman said, “Our engineers are working hard to fix the problem and we’re doing everything we can with the train operators to minimise the impact on their passengers.
“The railway in and around London is incredibly busy and even relatively small issues can have a big knock-on effect on passengers across the network.
“We know many people travelling into Victoria will have a difficult journey to work this Monday morning and are very sorry for the disruption caused.”