The protest in August 2023 came days after Sunak angered environmentalists by approving hundreds of new oil and gas licences in the North Sea off Britain's east coast.

The Greenpeace UK activists posted videos of themselves climbing onto the roof of Sunak's constituency residence in Richmond, northern England, and covering it with black sheets.

Two more activists unfurled a banner reading "Rishi Sunak -- Oil Profits or Our Future?" on the front lawn.

Amy Rugg-Easey, 33, Alexandra Wilson, 32, Mathieu Soete, 38, and Michael Grant, 64, had been accused of damaging 15 roof slates during the five-hour demonstration.

But a judge at York Magistrates' Court said the evidence against them was "so tenuous" there was no realistic prospect of securing a conviction.

The trial started in July but after the prosecution closed its case the defence argued that it could not be proved that damage to the roof was caused during the protest.

Sunak -- whose government lost power in a July general election -- and his family were away on holiday at the time.

His Conservative government had insisted that allowing new oil and gas licenses was essential to ensure Britain's domestic energy security and that it could still meet its 2050 net-zero goals.

He said that even if Britain achieved net-zero carbon emissions by mid-century around a quarter of its energy needs would still come from oil and gas.