Far-right political activist Tommy Robinson flew out of the UK as police made arrest enquiries after a man was knocked unconscious at St Pancras International Station.
The victim - seen lying face down on the concourse - suffered serious injuries and had to be taken to hospital after being given CPR by paramedics at the scene in central London.
Footage shared on social media shows the 42-year-old speaking to witnesses on Monday evening.
In an update, British Transport Police said: “Following a report of an assault at St Pancras station last night (July 28), officers have confirmed that the suspect, a 42-year-old man from Bedfordshire, boarded a flight out of the country in the early hours of this morning.
“Detectives are continuing to work closely to progress the investigation and bring him into custody for questioning.”
Robinson, whose real name is Stephen Yaxley-Lennon, later claimed in a video he had a fight with a door after showing off a cut on his forehead.
A concerned onlooker in the original clip on X, formerly Twitter, says: “Can we get someone here, quick?”
Robinson tell the man: “You saw him. He came at me bruv, you saw that, he came at me”. The video then ends.
He appeared to address the incident when he reposted X user Mike Hacks’ view a “pre-emptive strike is totally legal”, before adding: “Someone tried to attack him, and they came off worse.”
BTP said: “Officers were called to St Pancras station just after 8.40pm yesterday following reports of an assault.

“Officers attended and a man was taken to hospital with serious injuries, which are not thought to be life threatening.
“Overnight the investigation has been ongoing and officers have been making arrest enquiries.”
According to reports, a medical curtain was pulled up around the top of the escalators to platform B where a pool of blood has formed.
This happend today at St pancreas railway station. pic.twitter.com/4OLDCJSs1t
— London & UK Street News (@CrimeLdn) July 28, 2025
Forensic officers can be seen scouring the area and taking DNA samples from the handrail down to the platform.
London Ambulance Service used a blood transfusion bag to treat the victim.
One witness told LBC: “I saw around eight police vehicles - cars and a van, lined up outside on both sides of the station.
“I saw an unconscious man being worked on by paramedics – they erected curtains around him.
“They were trying to resuscitate him – and there was what looked like a blood transfusion bag.
“The station was still open as normal while the incident was being dealt with.”

Robinson shared Hacks’ post which claimed: “I know this will be controversial, but it’s true!
“It's never good or acceptable to physically assault someone over their political views. But let’s looks at the context.
“Tommy Robinson has been politically active and a well-known figure for years.
“There's countless videos of people debating him, threatening him etc. Shout and scream at him all you want, disagree with his views, debate him, argue with him...
“He’s not gonna punch or attack you. I’ve argued with him loads over the years and... guess what... never been attacked by him!
“But there has to be a limit point and a boundary that’s in place, and that applies to anyone.
“We should all be safe in our personal space. If you cross a line and attack someone physically, or threaten to attack them physically, then you can’t expect any response other than a strong one.
“A pre-emptive strike is totally legal. To me it looks pretty clear. Tommy Robinson - controversial or not - was going about his business. Someone tried to attack him, and they came off worse.”
Robinson was expected to be among protesters outside a migrant hotel in Epping on Sunday but failed to show up to the peaceful protests.
He was released from prison last month after he won his appeal to reduce his prison sentence at the High Court.
Robinson was approached by the Standard for comment.
Anyone with information or who witnessed what happened can text BTP on 61016, quoting reference 655 of 28 July.