All South West Train services from Dorking to London Waterloo have been cancelled until further notice due to signalling problems.
The issues have caused platforms 1 to 4 to be closed at the London terminus.
Customers are being advised to use Southern services, which will accept South West tickets.
On other routes, Southern Rail reports most trains operating as normal.
Meanwhile on the roads, a broken down vehicle on the M25 clockwise at junction 8 (Reigate) has closed one lane, causing...
