Train operators are asking passengers to check before travelling this evening as major disruption is affecting services at London Euston.
A fault with the signalling system at the London terminal means some lines are blocked.
Trains are subject to cancellation or delays by up to 100 minutes.
The fault was detected earlier today, with the hope it may be fixed by this afternoon, but disruption is now expected until the end of service today (2nd April)
Avanti West Coast passengers can use tickets with LNER between Kings Cross and Edinburgh, TransPennine Express, Transport for Wales, Northern, London Northwestern Railway, East Midlands Railway or Chiltern Railways.
Tickets will be valid tomorrow (3rd April) if you travel as close to your booked travel time as possible.
London Overground services will run between Watford Junction and Kilburn High Road only.
London Northwestern Railway has ticket acceptance in place with London Overground, London Underground, Thameslink, East Midlands Railway, CrossCountry, Chiltern Railways, Avanti West Coast and Stagecoach Buses.
Please check National Rail Enquiries for the latest travel advice.
