Labour has suspended the whip from the MP Mike Amesbury after footage appeared to show him punching a man to the ground, the party said.

A video published by the Mail appeared to show Amesbury, the MP for Runcorn and Helsby, hitting the man in the face and knocking him to the floor, before standing over him and aiming six more blows at his head.

The security camera footage also showed Amesbury shouting: “You won’t threaten me again, will you?”

A Labour spokesperson said: “Mike Amesbury MP has been assisting Cheshire police with their inquiries following an incident on Friday night. As these inquiries are now ongoing, the Labour party has administratively suspended Mr Amesbury’s membership of the Labour party pending an investigation.”

The move means he will not be counted as a Labour MP until further notice.

Amesbury said in a statement on Saturday night: “Last night I was involved in an incident that took place after I felt threatened on the street following an evening with friends. This morning I contacted Cheshire police myself to report what happened during this incident.

“I will not be making further comment but will, of course, cooperate with any inquiries if required by Cheshire police.”

Cheshire police confirmed a 55-year-old man had been voluntarily interviewed under caution in relation to the incident after officers were called to reports of an attack in the town of Frodsham at 2.48am on Saturday. “He has since been released pending further inquiries,” the force said.

Amesbury becomes the eighth MP to have the Labour whip suspended since the election in July, though the first to suffer such a fate because of allegations over their personal behaviour. The party suspended the whip from seven others in July after they defied the government in a vote over removing the two-child benefit cap.

Amesbury’s suspension came 24 hours after footage first circulated of the aftermath of the event, which showed him shouting while bystanders expressed shock at what had happened. That video shows a bystander pushing Amesbury away, while someone else says he is the local MP who has “smacked somebody on the floor”.

A Labour spokesperson said after that initial video: “We are aware of an incident that took place last night. We understand that Mike Amesbury MP approached Cheshire police to report what happened this morning himself and that he will cooperate with any inquiries they have.”

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Bridget Phillipson, the education secretary, said on Sunday morning: “Mike Amesbury is cooperating fully with the police. He’s gone forward himself to the police, and it is right that the police now look into this matter, investigate and decide what action, if any, is required.”

The party decided to toughen its stance after the publication of the second video, which showed details of the altercation itself.

The footage shows Amesbury talking to the man at 2.15am in Frodsham. It did not record the conversation between the two men, though the images appear to show it was not confrontational until shortly after the man looks to one side, at which point Amesbury punches him with enough force to knock him to the ground. The MP then stands over the other man, hitting him repeatedly as a third man tries to prise him away.

Amesbury was a shadow minister in the housing department before the election but was not given a government job after the party came to power. He won his seat with a majority of nearly 15,000 ahead of the second-placed party, Reform UK.