British police have said that a knife attack aboard a London-bound train which left 11 people in hospital is not being treated as terrorism, as two British nationals remain in custody on suspicion of attempted murder.

Armed officers made the arrests on Saturday after the train made an emergency stop at Huntingdon, around 130km north of the capital, following reports of multiple stabbings in a packed carriage. Counter-terrorism police assisted in the early stages of the inquiry, given the scale of the incident.

Superintendent John Loveless of British Transport Police confirmed on Sunday that there was currently “nothing to suggest that this is a terrorist incident”.

The suspects are understood to be a 32-year-old Black British man and a 35-year-old British man of Caribbean heritage. Both were born in the UK. Loveless urged the public not to jump to conclusions: “It would not be appropriate to speculate on the cause of this incident.”

Of the 11 injured passengers taken to hospital, four have since been discharged. Two remain in a critical, life-threatening condition.

Prime Minister Keir Starmer condemned the attack as “appalling” and “deeply concerning”, while King Charles said he was “truly appalled and shocked”. Home Secretary Shabana Mahmood said she was “deeply saddened” and appealed for restraint, warning against online speculation.

The government has been particularly wary of misinformation since riots erupted in 2024 after false claims spread on social media following the murder of three girls in Southport.

Passengers described scenes of panic and bloodshed. One witness, Olly Foster, told the BBC: “Someone ran past me saying a man was stabbing everyone… I looked at my hand and it was covered in blood. There was blood on the chairs ahead of me, blood everywhere.” Another eyewitness told Sky News a suspect was brandishing a large knife before being tasered by police.

Britain’s terrorism threat level remains at “substantial”, indicating that an attack is considered likely. While the country has experienced fewer major attacks in recent years compared with 2017, three people were killed last month in a stabbing at a Manchester synagogue.

Police say enquiries are ongoing and a visible security presence will remain in the area as officers reassess passenger safety.