UK MP Iain Duncan Smith says the British government should expel Chinese diplomats if they were involved in an attack on a Hong Kong protester.
Bob Chan says he was beaten inside the compound of the Chinese consulate in Manchester.
Amateur footage of the protest appears to show a man on the ground inside the Chinese consulate being beaten.
"The government must say categorically, 'Anybody involved in those scenes is not welcome here'," said the former leader of the Conservative Party at a news conference.
"If it's the consul themselves, they must go. And they should call the ambassador. And that's the key thing. Call the ambassador, and tell the ambassador, we want a full apology and these people are persona non grata, they're going home and we will never tolerate that on British soil."
Duncan Smith has been a key critic of China. He was one of the lawmakers sanctioned by Beijing last year for spreading "lies" about alleged human rights abuses in the Chinese region of Xinjiang.
Also present at the news conference, Chan backed the call for action.
"It's very disturbing. This incident reflects that Chinese consulate staff have totally no regard for the law. I believe the UK is a very safe place, with freedom of speech.
"That consulate staff can so brazenly pull someone inside and beat them up in broad daylight is unimaginable. It's shocking and this should happen."
China's foreign affairs ministry claims a protester was there illegally and had "jeopardised the security of the Chinese diplomatic premises". They also blamed the police for not intervening sooner and that staff were forced to defend the grounds themselves.