A jury has been shown footage showing the moment a father was stabbed to death on a train in a “quick and frenzied attack”.
The Old Bailey heard Lee Pomeroy, 51, suffered 18 knife wounds in an assault lasting little more than 25 seconds.
His 14-year-old son told jurors he witnessed the confrontation between his father and another man on a train seconds before the stabbing.
Darren Pencille, 36, of Wilbury Road in Farnham, denies murdering Mr Pomeroy.
He has admitted possessing a bladed article and his barrister Justin Rouse QC said the defendant did not deny stabbing Mr Pomeroy but would be arguing that he was acting in self-defence.
Mr Pomeroy’s son told the court he had not noticed Mr Pencille board the train at the same station as he and his father.
But he said the two men exchanged words and he added: “The guy said ‘Come on, get off at the next station’ and my dad took that as a threat and got up with a clenched fist.”
He said: “I could hear them shouting at each other. I don’t remember seeing when the fight started. I think I could hear them shouting. I looked behind again. I see them punching each other.”
Describing his father, he told jurors: “Normally when someone says something to my dad, he won’t let it go.
“Dad never really starts a fight. I have never seen my dad not reply to something like that.”
Jurors watched in silence as they viewed the CCTV footage, which initially showed Mr Pomeroy and his son buying tickets at the station and then boarding the train at London Road at the same time as Mr Pencille.
It showed the two men arguing before Mr Pomeroy followed Mr Pencille into another carriage, while his son remained where he was.
The footage then showed Mr Pomeroy being repeatedly stabbed while trying to defend himself with his hands.
Det Con Marc Farmer, from British Transport Police, told the court: “We see the first blow (that was to his neck), and then movement and we see him slash at his torso and then his thigh.
“It is quick and a frenzied attack.”
Det Con Farmer confirmed to Mr Rouse that there was no audio of the apparent verbal exchange.
The barrister said Mr Pencille walked away and was followed by Mr Pomeroy – which the police officer also confirmed.
“At the end of the carriageway is a dead end,” Mr Rouse continued. “He can’t get out.”
Mr Rouse added: “The train is in motion and he can’t get out of the doors. Before he turns to violence he resorts to using his phone.”
Det Con Farmer replied: “Yes.”
Mr Rouse then said: “After the blows have been exchanged – and there is no dispute Mr Pencille stabbed Mr Pomeroy – Mr Pomeroy then for the first time retreated, and it’s fair to say Mr Pencille doesn’t take a single step towards him.”
Det Con Farmer replied: “Only to pick up his glasses.”
Witnesses who had been in the same carriage as the pair told the court they had been scared for their lives.
Megan Fieberg told the court she heard the two men swearing at each other and added: “They were physical but I didn’t see the whole stabbing situation. I had already left the carriage by then.”
Describing what Mr Pomeroy was saying, she said he “wanted an apology” from Mr Pencille for humiliating him in front of his child.
Mr Rouse asked whether Mr Pomeroy had been mocking Mr Pencille and Mrs Fieberg replied: “Yes.”
He said: “You never heard anything like ‘I’m going to kill him’.”
She replied: “No.”
Mr Pencille’s girlfriend, Chelsea Mitchell, 27, of the same address, denies assisting an offender.
The trial continues.