Eco activists scaled Labour’s London headquarters on Monday and doused its front steps in black paint.
Members of Extinction Rebellion set off smoke grenades on the roof of the building in Blackfriars Road, Southwark.
The protest group said they are demanding any future Labour government takes “urgent action” to cancel hundreds of new oil and gas exploration licences in the North Sea announced by the Prime Minister earlier this year.
Heather Wilde, 18, from Lincoln, said: “I am terrified for my future, our leaders have totally let down my generation.
“Labour has scaled down its commitment to fund the transition to clean energy, saying it will wait until the economy grows first.”
One protester chained himself to a handrail outside the party's offices.
They carried signs that read: “Labour: Cut The Ties to Fossil Fuels”.
Sir Keir Starmer had pledged to ban new North Sea oil and gas licences as part of Labour's commitment to make Britain a "clean energy superpower".
However the Labour leader has now reportedly reassured the Norwegian owners of Rosebank, the UK's largest undeveloped oil field, he would not block drilling development there if he won the next general election.
The party has also signalled a retreat from its plans to revoke all new licences in the North Sea, following criticism from trade union leaders.
XR activist Marcus Bailie, 68, from South Wales, said: “We demand an end to all new fossil fuel licences, including cancelling any awarded by this zombie Tory government before the next election.
"Emissions must peak by 2025, opening a huge new oilfield like Rosebank would make that impossible. Starmer should be warning fossil fuel companies now that any new licences will become stranded assets.”
Mr Sunak has said fossil fuel exploration in the North Sea will make Britain more energy independent.