Greenpeace activists, angered by Britain’s decision to issue new licenses for oil and gas exploration in the North Sea, took their opposition to Prime Minister Rishi Sunak on Thursday — or at least to the rooftop of one of his homes.
With apparent ease and unhindered by security guards, the four protesters walked onto the grounds of the manor house Mr. Sunak owns in the village of Kirby Sigston in North Yorkshire, climbed onto the roof and draped the facade with panels of black fabric.
“It really was about this image of pouring oil all over the prime minister’s house,” said Ami McCarthy, a political campaigner for Greenpeace, who said Mr. Sunak was choosing profits over addressing climate change. “We need our prime minister to stop being so hellbent on fossil fuels.”
Mr. Sunak and his family, who live in London, were not at the residence at the time, the North Yorkshire police said, and the four protesters were eventually arrested after spending several hours spent on the roof. They were taken into custody on suspicion of causing criminal damage and public nuisance.
Conservative lawmakers condemned the episode and said that the demonstrators had gone too far.
“Politicians live in the public eye, and rightly receive intense scrutiny, but their family homes should not be under assault,” said Alicia Kearns, chairwoman of Parliament’s Foreign Affairs Committee, calling the actions of the group “unacceptable.” Before long, she said, police officers may have to be stationed outside the home of every member of Parliament.
The protest raised concerns over the security of the leader of the British government. Mr. Sunak currently lives at prime minister’s official Downing Street residence, but the $2.3 million manor house in the Yorkshire countryside is among several properties that he and his wife, Akshata Murty, own.
Downing Street declined to comment on the Mr. Sunak’s security. But John Moore, the managing director of Westminster Security, a high-end private security company based in London, said the incident was “a major security failure.”
“They shouldn’t have been able to enter the grounds, never mind scale the building,” he said.
Ms. McCarthy, the Greenpeace campaigner, did not participate in the demonstration but received updates, and said the activists had not encountered a visible security presence at the home.
“It’s not exactly Fort Knox,” she said.
Ms. McCarthy said that the protesters had “literally just walked in through a gate,” and that they “didn’t have to break anything or do anything to gain access.”
Ms. McCarthy said that group had planned the protest to coincide with a family vacation by Mr. Sunak, who flew to the United States on Wednesday. The protesters, she said, intended to be nonviolent, and knocked on the door to ensure that nobody was at the property. She said they also cooperated with the police when they arrived.
It is not the first time that Greenpeace activists have staged a protest around Mr. Sunak’s Yorkshire home. In March, they gathered outside it in swimwear to protest reports that Mr. Sunak had upgraded the local electricity network to help heat a pool.
Mr. Moore, the security director, said the protesters had highlighted a flaw that could be exploited by people who might want to harm the prime minister’s family or damage the property. “It’s very embarrassing for the prime minister,” he said.
Security measures for British lawmakers have been tightened in the wake of several attacks on public figures, including the killing of Jo Cox, a member of Parliament, in 2016. Mr. Sunak, as prime minister, receives an additional layer of protection, and police officers are permanently stationed at Downing Street. Prime ministers retain protection even after they leave office.
Environmentalists and climate change activists have ramped up protests in Britain recently, and governments have given the authorities more purview to crack down on disruptive demonstrations. Rights groups have said that they fear that the powers are eroding basic rights, like freedom of expression and assembly, and creating more combative protest situations.