Mark Field was caught on video assaulting the Greenpeace activist

A minister in charge of India in the UK's Foreign and Commonwealth Office (FCO) was suspended on Friday after footage showed him "grabbing" and forcibly ejecting a climate activist at a political event in London.

Mark Field, Britain's minister of state for Asia and the Pacific, was a guest at the formal black-tie dinner event at Mansion House in London on Thursday, where UK Chancellor Philip Hammond was making a keynote speech on the state of the UK economy when he was interrupted by female protesters from the Greenpeace environmental organisation.

Mr Field was caught on camera getting up from his seat to confront one of them and forcing her towards the exit.

Greenpeace accused the minister of a "disproportionate" reaction to their protest and called for an investigation.

"He will be suspended as a minister while investigations take place," a Downing Street spokesperson said.

"The Prime Minister has seen the footage and found it very concerning. The police have said they are looking into reports over this matter and Mark Field has referred himself to the Cabinet Office and Conservative party," the spokesperson said.

The City of London Police confirmed it had received reports of an assault and are investigating, but no arrests have been made.

"We have received a small number of third-party reports of an assault taking place at the event. These reports are being looked into by police," a police statement said.

A number of Opposition party MPs also called for action against Field and called for him to resign.

Defending his actions, the minister insisted he was responding to a "major security breach" and said that he "instinctively reacted" as he feared the protesters may have been armed.

He has since apologised to the woman and referred himself for investigation to the UK Cabinet Office.

He said: "I grasped the intruder firmly in order to remove her from the room as swiftly as possible."

"I deeply regret this episode and unreservedly apologise to the lady concerned for grabbing her but in the current climate I felt the need to act decisively to close down the threat to the safety of those present," he said.

Greenpeace said that the storming of the meeting was intended to remind the government about the climate emergency.

Around 40 of its volunteers had "gatecrashed" the event, most dressed all in red and wearing sashes bearing the words "climate emergency", and attempted to read out a message and "drown out" Hammond''s keynote address.

"This is a climate emergency. Business as usual is no longer an option," said Areeba Hamid, climate campaigner for Greenpeace UK.

"The real bottom line, the priority that needs to come before all others, is not profit, revenue or growth, but survival. That needs to be recognised in every boardroom and on every balance sheet, starting with the Chancellor's," she said.

The City of London Corporation, organisers of the annual event, said they would review their security in light of the event.