South West Trains said urgent repairs were being undertaken to the railway at London Waterloo, meaning ‘fewer trains are able to run on some lines’.
The firm said: ‘Train services running across the whole South West Trains network will be cancelled, delayed by up to 30 minutes or revised. Disruption is expected until 15:00 10/04.
‘A track defect over a set of points has blocked platforms 1-4. This is causing major disruption to trains in and out of London Waterloo.’
The company has said selected Portsmouth Harbour to London Waterloo services will terminate and start at Guildford.
‘Train services that are running may have to be altered or revised at short notice. Some services may also be diverted via an alternative route,’ South West Trains added.