A project manager shared on Sunday her terrifying encounter with an attacker who ominously declared, “The Devil is not going to win,” as she pleaded for her life.

Dayna Arnold, 48, was traveling on the train with her partner, Andy Gray, 37, a site manager, when the harrowing incident unfolded shortly after they boarded.

The pair were seated in Coach J, but chaos erupted, and Dayna found herself separated from Andy as passengers scattered in panic.

Amid the commotion, she stumbled to the ground, only to find the attacker looming over her, brandishing a 6-inch knife, as she uttered, “Please don’t.”

Recounting the ordeal, Dayna said, “I was fleeing, and when I glanced back, I saw him chasing me.

I tripped, and all I could say was, ‘Please don’t.’ He paused momentarily, his expression changed, and he continued on, stating, ‘The Devil is not going to win.'”

She told The Mirror: ‘We just feel very lucky today. If we had been sat at the other end of the carriage, we’d might not be here.’

Andy – who was still wearing the blood-splattered jumper he was dressed in on the train – said he first saw the first bloodshed minutes after pulling out of Peterborough station.

Dayna Arnold, 48, boarded the train with partner, site manager Andy Gray, 37, before the incident began minutes later

Cassie Marriott, pictured, was with her mother and sister when she saw shocked passengers outside the station after the bloody incident

British Transport Police has declared the attack a ‘major incident’ and is probing the stabbing spree alongside counter-terrorism police (Pictured: The train sitting at the platform on Sunday morning)

He said: ‘We were on the same carriage. Within about five minutes we just heard the panic and commotion in people’s voices.

‘I didn’t see him but I saw the knife moving, plunging. I pushed Dayna but we were separated. There was this young lad who was about 19 or 20.

‘He had gashes on his arm and a severe puncture under his arm. There was a lot of blood coming out of him.

‘He said, “I’ve been stabbed, please help me.” It looked like an artery had been hit. I took off my belt and made a tourniquet. He was saying, “Please call my dad, I don’t want to die”.’

Dayna and Andy fled the station and were given a complimentary room at a nearby pub.

They returned to Huntingdon station on Sunday to travel down to Milton Keynes.

Andy said: ‘I still have [the victim’s] blood on my jumper. I heard there were two people critical so I hope we saved his life.’

Cassie Marriott, of Huntingdon, was with her mother and sister when she saw shocked passengers outside the station after the bloody incident.

Police cars and ambulances pictured outside Huntingdon Station in Cambridgeshire

She told the Daily Mail: ‘I saw a young lad who had blood on his lap. My sister went over to him and asked if he was okay. He said yes, it’s not my blood.

‘He was stood there staring into nothingness, completely shell shocked.

‘He was in his late teens or early 20s. He was just a kid.’

Ms Marriott, 30, an admin worker said they then spoke to a young couple called Maisie and James who had been confronted by the knifeman.

‘He was doing his A-levels. He was meant to be getting ready for an English exam,’ she said.

‘He said he was listening to techno and she was listening to Queen and Oasis then suddenly there was a man with a knife.

‘She said, “he went to stab me but someone pulled me out of the way and got in front of me”.’

Ms Marriott said the young woman had fled the train, leaving her bank cards and phone behind and only had her vape.

Maisie, who was heading towards Stevenage, told her she thought the attacker had got on the train at Grantham.

She was ‘visibly shaken but calm, some nervous laughter’, Ms Marriott said.