The attack occurred on the 6.25pm LNER service to King’s Cross on Saturday evening, forcing the train to make an emergency stop at Huntingdon station in Cambridgeshire.

Witnesses said police officers boarded the train and tasered a man carrying a knife.

British Transport Police said eleven people were taken to hospital. Nine passengers were initially reported to have life-threatening injuries, but four have since been discharged. Two victims remain in critical condition.

Police confirmed that both suspects, one aged 32 and the other 35, were born in the United Kingdom.

Supt John Loveless said: “British Transport Police declared a major incident yesterday, and counter-terrorism policing were initially supporting our investigation. However, at this stage, there is nothing to suggest that this is a terrorist incident.”

Defence Secretary John Healey called it an: “isolated attack” but warned that Britain was entering a: “new era of threat.”