Greta Thunberg joined a protest against government plans for new oil and gas licences outside the venue where Prime Minister Rishi Sunak gave a speech on foreign policy.

The 20-year-old Swede was among demonstrators from Fossil Free London objecting to plans for fresh drilling at Rosebank off the Scottish coast.

She joined a group of around 50 activists for the protest which took place as attendees arrived for the Lord Mayor’s Banquet at London’s Guildhall.

The activists – who banged pots, pans and drums – were split into two groups and around 20 police officers formed a line to prevent them entering the venue.

Protesters carried banners saying “Rosebank will kill us” and “Stop Rosebank”, and at one point sang “Oh Rishi is trying to kill us” to the tune of We Wish You A Merry Christmas.

Fossil Free London spokesperson Joanna Warrington said: “Sunak and his climate-wrecking Government are selling the UK public a dangerous pipe dream.

“They are falsely promising energy security through the expansion of new oil and gas, that if pursued would only spell utter climate disaster, and an insecure, warming world for all of us that live within it.

“Whilst Sunak dines with the Lord Mayor, bankers and business leaders at the heart of obscene wealth in this country; we are outside with a clear message.

“We want a liveable future; and secure, affordable, renewable energy for all.”

In August, the Prime Minister said he wants to “max out” the UK’s remaining oil and gas reserves as he announced plans for new drilling at Rosebank and other North Sea oil fields.