Travel disruption between Balham and Clapham Junction is expected to last all of tonight after a fault was found with the signalling system.

National Rail has warned tonight (February 7) this will result in fewer trains being able to run on some lines towards London, and services may be cancelled or delayed by up to 25 minutes.

This is because repairs cannot take place while trains continue to run.

A National Rail spokesman said: “Services will have to run non-stop between Selhurst and Clapham Junction in order to reduce congestion on the network.

“Thornton Heath, Norbury, Streatham Common, Balham, and Wandsworth Common will have a less frequent service into London Terminals and Milton Keynes Central.

“It is anticipated that this will have no effect on tomorrow morning’s train service.

“Thameslink services will experience delays on the Wimbledon route as they cross over with this busy part of the network.

“If you are travelling to Milton Keynes Central, please board the next available service and change at Clapham Junction for connecting services.”

Gatwick Express, Southern and Thameslink services are all affected by the disruption.