Tommy Robinson has been released on bail after being arrested over an alleged assault at St Pancras station in central London.
The 42-year-old far-right activist was arrested at Luton Airport on Monday evening in connection with the incident which took place on 28 July.
Footage on social media appeared to show Robinson, whose real name is Stephen Yaxley-Lennon, walking back and forth next to a man lying motionless on the ground.
British Transport Police (BTP) said on Tuesday he has been released on police bail until 2 September while enquiries continue.
He was arrested on suspicion of grievous bodily harm and taken into custody after arriving in the UK on a flight from Faro in Portugal.
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He had been wanted for questioning after leaving the country for Tenerife in the early hours of 29 July, BTP said.
The other man seen in the footage was taken to hospital with “serious injuries” but was discharged on 30 July, the force added.
