Rail passengers heading into London following the bank holiday are facing severe delays tonight on one of the UK's key train routes.
Overhead wire problems between Peterborough and Stevenage have caused extensive disruption to services on the East Coast main line heading into London King's Cross.
The problems have affected a number of train operators who have warned passengers the issue will ongoing for the rest of the evening.
According the East Coast website, East Coast and Grand Central services between Peterborough and King's Cross are being delayed by up to two hours.
It said: "Replacement buses have been requested to run between Peterborough and London King's Cross, however there is no estimate as to when they will be available."
First Capital Connect services between Peterborough and King's Cross are running between Huntingdon and London King's Cross only and the problems have also affected F irst Hull Trains services.
First Hull Train issued advice to passengers which said: "Owing to overhead wire problems between Grantham and London King's Cross all lines are blocked.
"Impact: Train services running to and from these stations may be cancelled or delayed at short notice."
Frustrated passengers took to Twitter tonight.
Gemma Chandler said: " I've been sitting on a stationary @eastcoastuk train at #Peterborough for 1hr45mins & we haven't had an announcement update for 55mins."
Amy Firth posted: "@ eastcoastuk It's carnage here at #Peterborough with masses still attempting to get on this train. any updates??."
A spokesman for East Coast said the line was blocked by a train from another operator stuck at the scene of the overhead wire problem, which is about five miles from Peterborough.
He said the firm was running replacement diesel trains via Cambridge, which added considerable times to journeys, and also providing coach services to St Neots, where passengers could pick up First Capital Connect services.
The spokesman said additional staff were being brought in, including at King's Cross. But he said the main problems were with passengers heading south rather than out of the capital.
He said: "We are very sorry for the disruption to journeys this evening. We are bringing in additional staff and trains where we can and coaches where we can't."
The spokesman also said tickets would be valid tomorrow.
A Network Rail spokeswoman said the problem was reported at 6.10pm.
She confirmed a train was stuck at the scene without power and arrangements were under way to bring another service alongside to enable passengers to be transferred.
She also said it was not known at this time what caused the overhead wire problem but engineers were working to fix the fault.