Network Rail has warned that Jarvis faces "repercussions" after the contractor admitted a maintenance oversight may have led to a train derailment on Tuesday.
Jarvis said that the failure to make a final disconnection during overnight maintenance on a signalling system was the likely cause of the derailment of the 7am service from King's Cross to Glasgow.

A spokesperson for Network Rail said that the body was investigating the crash and that meetings with Jarvis were being arranged. The spokesperson said: "I'm sure there will be high-level discussions. There will be repercussions."

Jarvis said in a statement that it apologised for any inconvenience, but pointed out that no injuries had been reported.

The company's safety record has been under the spotlight since the Potters Bar rail crash last year. A Health & Safety Executive report concluded that poor maintenance was the most likely cause.