The anti-Islam activist Tommy Robinson has been filmed punching an England fan to the ground outside a football stadium in Portugal.

Robinson, whose real name is Stephen Yaxley-Lennon, can be seen walking purposefully toward the man before striking him in the head.

Footage shows the man falling to the floor as Robinson shouts: “Fuck about again you’ll get knocked out again, bruv.”

The video appears to have been filmed outside the Estádio D Afonso Henriques in Guimarães, where England lost 3-1 to the Netherlands in a Uefa Nations League semi-final match on Thursday night.

The incident took place little more than a week after the English Defence League founder’s humiliating defeat in the European elections.

Deputy chief constable Mark Roberts, the lead for football policing on the National Police Chiefs’ Council, said: “We have been informed of an incident outside the Guimarães stadium last night and the footage has been passed to our counterparts in Portugal for further investigation.

“As with all the disorder that has taken place in Portugal over the past few days, anyone found to be involved in disorder could be subject to a banning order on their return to the UK.”

In a message to his supporters on Friday, Robinson showed no remorse. He said he had been defending himself and was “fed up of being a punchbag for people”.

Robinson, who has at least five convictions for violence and public order offences, said: “I was walking through there – I hadn’t had a drink, I was with my wife – that man … come up to me twice getting rowdy, in my face, being abusive, being aggressive.

“You can see his friend has his hand on him and I said to my wife: ‘I can see where this is going to go, walk away,’ and I said to the man’s friend, ‘Keep that man away from me.’ He comes back up to me again like that and watch what happens to him.”

The footage shows Robinson, 37, striding towards the man saying “Who said that?” But it is not clear what the other man is supposed to have said.

Addressing supporters on Telegram, Robinson said: “I’m not going to wait for him to attack me. Twice I warned him. Twice I warned his friends.

“All those people there with him, they’re not my friends, their his. Four of them are his friends. I told them: ‘What does he think he’s doing? Keep him away from me.’ The man should keep his opinions to himself and his mouth to himself.”

In a separate video published by Robinson, the Luton-born activist is shown being challenged by a man inside the stadium about the incident.

Robinson can be seen remonstrating with the man before saying: “Think about it. You’re with your friends and I’m with my wife. Think about how much of a wanker that is. You’re an absolute wanker, bruv. And that’s what I said to you. If you’ve got a problem, say it to my face.”