A serious signal failure on South West Trains is causing commuters in the south face major problems this morning.
A complete loss of signalling has caused all lines to be blocked between London Waterloo and Woking.
Train services across South West Trains are now expected to be cancelled, revised or delayed by up to 90 minutes.
The company says it expects the significant disruption to continue until 2pm on Monday 24th July 2017.
A spokesperson said, "South West Trains passengers are being urged not to travel towards London Waterloo this morning and a queueing system may be in place to assist with passenger flows in and around stations.
"All lines are currently blocked. This incident has only just occurred and we are gathering further information which will be made available once known. Our engineers are on site and are working hard to restore the signalling so we are able to run trains."
The following trains have been cancelled:
05:47 Dorking to London Waterloo due 06:40
06:44 Alton to London Waterloo due 07:49
06:50 London Waterloo to Guildford due 07:47
07:58 Guildford to London Waterloo due 09:12
09:20 London Waterloo to Woking due 10:08
10:32 Woking to London Waterloo due 11:22
11:33 London Waterloo to Guildford due 12:34
South West Train tickets will be accepted on the following routes:
Great Western Railway