A lawmaker from the governing Labour Party was suspended from the party on Sunday after he appeared to punch a passerby who he said had been threatening him after a Friday night out with friends.

Mike Amesbury, 55, was suspended after CCTV footage showed him talking to the man, throwing a first punch and repeatedly hitting him after he was knocked to the ground.

Another video showed the aftermath of the punch, where he could be heard saying “you won’t threaten the MP ever again” to someone off camera.

A Labour Party spokesperson said Amesbury, the Member of Parliament for Runcorn and Helsby in north-west England, was assisting police with their inquiries.

“As these inquiries are now ongoing, the Labour Party has administratively suspended Mr Amesbury’s membership of the Labour Party pending an investigation,” the spokesperson said.

In a statement on Saturday, before the video of the punch emerged, Amesbury said he “felt threatened on the street following an evening out with friends,” and had contacted the police himself to report the incident.

“I will not be making further public comment but will of course co-operate with any inquiries if required.”

There was no immediate response to a request for fresh comment on his suspension on Sunday.