The police have not yet pressed charges in connection with the incident, although one individual remains detained.

Here is what is currently known about the incident.

On Saturday night at approximately 7:42 pm local time (6:42 am Sunday AEDT), passengers aboard a train headed to London from Doncaster began contacting the police. They reported that individuals were running through the train cars and taking refuge in the restrooms.

The train’s driver, who has been revealed to be a military veteran, executed an emergency stop at Huntingdon, roughly 120 kilometers north of London.

In a swift response, police officers arrived at the scene and detained two men around 7:50 pm local time, merely eight minutes after the initial distress calls were made.

Ten people were taken to hospital, while an 11th later self-reported.

In their initial response, police treated the mass stabbing as a potential terror incident, broadcasting the code-word “Plato” to responding officers – the term used to indicate a “marauding terror attack”.

However, authorities have since walked that back, without speculating further as to motive.

“This is a shocking incident and my thoughts are with those who have been injured and their families,” British Transport Police Superintendent John Loveless said outside the station in Huntingdon in eastern England where the train halted soon after the attack.

“There is nothing to suggest this is a terrorist incident.”

Six people remain in hospital as of this morning (AEDT), with one in a critical condition.

That person has been identified as a railway staffer who tried to stop the attack, and who police say saved lives with his “heroic” actions.

Five other people have been discharged from hospital.

Who were the men arrested?

A 32-year-old man and a 35-year-old man were both taken into custody at the scene.

However, this morning, police confirmed they had released the 35-year-old man without charge, saying he had not been involved.

The 32-year-old remains in custody.

He has been identified as a British national.

It is likely the sole remaining suspect will be charged once police have finished their interrogation.

London North Eastern Railway, or LNER, which operates the East Coast Mainline services in the UK, confirmed the incident had happened on one of its trains and said there would be major disruption on the route until Monday local time (Monday evening/overnight AEDT).

Loveless said passengers will see a “high visibility presence of police officers at stations and on trains” on Sunday.

Reported with additional details from Associated Press.