Tory MP Mark Field has been suspended as a government minister for an “over the top” response to a climate change protester he manhandled at a high-profile dinner.
Prime Minister Theresa May made the decision to suspend him from his Foreign Office job after viewing footage of the incident, which she found “very concerning”.
Greenpeace activist Janet Barker said she had expected some resistance to the group’s protest but not to be “grabbed round the neck” and physically removed from the room.
City of London Police said they were looking into a “small number” of third-party reports of an assault at the Mansion House event.
Greenpeace protesters disrupted the black-tie event, where Chancellor Philip Hammond was speaking, to demand action to tackle the climate emergency.
Mr Field was seen grappling with the female protester in scenes described as “horrific” by Labour.
A Downing Street spokeswoman said: “The Prime Minister has seen the footage and she found it very concerning.
“The police have said they are looking into reports over this matter and Mark Field has also referred himself to both the Cabinet Office and the Conservative Party.
“He will be suspended as a minister while investigations take place.”
Mrs May is understood to have spoken to Chief Whip Julian Smith about the incident, who then informed Mr Field of her decision.
Ms Barker told the BBC she had expected resistance “but not to the extent which I received”.
“I expected to maybe engage in a conversation or two with people, perhaps people blocking my way.
“But certainly not to be grabbed round the neck.”
Asked what she thought of his actions, she said: “They were pretty much over the top.
“We were peaceful, I was simply walking past his chair - or trying to walk past his chair. They were really over the top.”
Mr Field has apologised “unreservedly” to the activist.
In a statement to ITV, Mr Field said: “In the confusion many guests understandably felt threatened and when one protester rushed past me towards the top table I instinctively reacted.
“There was no security present and I was for a split-second genuinely worried she might have been armed.
“As a result I grasped the intruder firmly in order to remove her from the room as swiftly as possible.”
He said he “deeply” regretted the incident and would co-operate with an investigation.