Greta Thunberg has been charged with a public order offence following an environmental protest in London earlier this week. 

The 20-year-old is due to appear at Westminster Magistrate's Court on November 15 accused of failing to comply with a condition imposed under Section 14 of the Public Order Act. 

She was one of 26 people charged by the capital's Metropolitan Police, after she was held at Tuesday's demonstration.

Footage from the protest showed her being removed by two police officers from the protest outside the energy sector's annual London get-together at the five-star hotel.

UK police confirmed the charges against the Swedish activist, who has become a key face of the movement to fight climate change.

Joining a mass protest, Thunberg had slammed "closed door" agreements struck between politicians and representatives of the oil and gas industry.

"Behind these closed doors, spineless politicians are making deals and compromises with lobbyists from (the) destructive fossil fuel industry," Thunberg told journalists outside the venue hosting the annual gathering, which runs until Thursday.

Several hundred protestors gathered by the InterContinental London Park Lane hotel during the "Oily Money Out" demonstration, organised by pressure groups Fossil Free London and Greenpeace, blocking all entrances to the venue.

The carbon-intensive sector has faced fierce criticism from the green lobby for continuing to invest in dirty fossil fuels and worsen climate change -- instead of accelerating the shift towards cleaner renewable energy.