A flooded railway at Clapham Junction is causing delays and cancellations this morning (Wednesday October 2).
Disruption is expected until 9:00am, it is reported.
A statement on the National Rail website reads: "You may find that your train is delayed after being affected by congestion in the Clapham Junction area. This is because trains are running at reduced speeds on some southbound lines (away from Central London).
"Network Rail have discovered flooding in the Clapham Junction area. This is preventing the signalling equipment from working properly at Falcon Junction, which is between Clapham Junction and Wandsworth Common stations, on the lines used by stopping services around South London and services to and from Milton Keynes Central.
"Some trains are being diverted onto alternative lines, which has caused some congestion."