Tommy Robinson has been released on police bail after being arrested over an alleged assault at St Pancras railway station.
The 42-year-old, whose real name is Stephen Yaxley-Lennon, was arrested at Luton Airport on Monday evening in connection with the incident which took place on July 28.
Footage shared on social media appeared to show Robinson pacing around the London station with another person lying still on the floor nearby.
British Transport Police (BTP) said on Tuesday that he has been released on police bail until September 2 as inquiries continue.
The activist said in a lengthy video on social media that he acted in self-defence after a man physically confronted him.
He urged the police to share the CCTV footage of what happened.
Robinson was arrested on suspicion of grievous bodily harm and taken into custody after arriving in the UK on a flight from Faro in Portugal.
He had been wanted for questioning after leaving the country for Tenerife in the early hours of July 29, BTP said.
Robinson said he went to the Spanish island on a pre-booked trip and that he told police where he was as well as the date of his return.
The victim was taken to hospital with what police described as serious injuries and he was discharged last Wednesday.
