UK's Starmer insists party acted swiftly over 'shocking' MP brawl video

Britain's ruling Labour party announced late Sunday that it had suspended Mike Amesbury, hours after the Mail Online published a video seeming to show the lawmaker punching a man to the ground.

In the footage, the attacker then repeatedly hits him as others nearby shout: "Stop it".

"It's shocking," Starmer said as he took questions from the media following a speech ahead of his government's first budget later this week.

"We moved very swiftly to suspend him as a (party) member, and as a member of parliament. There is now a police investigation."

The UK leader declined to say anything further about the incident allegedly involving Amesbury, 55, a backbench MP representing a parliamentary seat in northwest England.

Police have confirmed a 55-year-old man was voluntarily interviewed under caution in relation to the incident, which occurred in the early hours of Saturday.

Cheshire Police said officers had been called to reports of an attack in the town of Frodsham, and that "further inquiries" were ongoing.

A spokesman for the Labour Party, which took power in Britain in July, said: "Mike Amesbury MP has been assisting Cheshire Police with their inquiries" following the incident.

"As these inquiries are now ongoing, the Labour Party has administratively suspended Mr Amesbury's membership of the Labour Party pending an investigation."

Amesbury has said in his own statement that he will "co-operate with any inquiries" but was "determined to remain an open and accessible MP for our community".

He added he had been "involved in an incident that took place after I felt threatened on the street following an evening out with friends".

He noted he had "contacted Cheshire Police myself to report what happened during the incident".

"I will not be making further public comment but will, of course, co-operate with any inquiries if required by Cheshire Police."

In July last year, a 56-year-old man was convicted of stalking the MP at his constituency office in Frodsham.

Prosecutors said the man had been seen staring through the glass and asked guards about their level of security.