Gatwick Express services have been suspended all day on Friday after a points failure at London Victoria.
The points failure is causing disruption on the Southern and Gatwick Express routes to and from London Victoria - and means the Gatwick Express won’t run.
Passengers are being warned that other services for Gatwick may be much busier than normal.
In addition, Southern services which run to and from London Victoria may have a number of delays and service changes
To avoid the issues at London Victoria, some trains may be diverted to run to and from London Bridge, which may also mean a reduced service at Clapham Junction at certain times.
In a message to customers, the company said: “Due to a points failure, Gatwick Express services that run between Brighton and London Victoria will be suspended all day today, Friday 11th October.
“Journeys may take an extra 15 minutes than longer, so please allow some extra time and check before you travel.”
In addition, on October 12 and 13, all Gatwick Express services to and from London Victoria, as well as all Southern services to and from London Victoria will not run to planned engineering work.
Engineering work is taking place at Victoria, closing all lines used by Gatwick Express and Southern services.
Instead, those who were planning to travel with Gatwick Express, can use other Southern and Thameslink trains between Gatwick Airport and London Bridge.
Earlier on Friday, Southern and Thameslink services were also hit by disruption caused by a fault with the signalling system between East Croydon and Oxted.
This has now ended.