‘We are doing what the government won’t’: Greenpeace dumps nine giant boulders signed by celebrities including Benedict Cumberbatch and Simon Pegg into the North Sea to create a 45-square-mile underwater barrier against industrial fishing

The Southern North Sea Marine Protected Area (MPA), designated to safeguard marine wildlife, has recorded the highest level of bottom-trawling activity among the UK’s offshore protected sites. Now, in an unusual attempt to protect its marine biodiversity, Greenpeace activists have dropped nine giant limestone boulders onto the seabed, creating what the organisation describes as an underwater barrier against industrial fishing.The boulders, each weighing up to two tonnes, were deployed from Greenpeace’s vessel Arctic Sunrise on October 31, approximately 50 km off England’s eastern coast. The organisation announced the operation on November 2, claiming that the strategically placed rocks had effectively closed 116 sq km (approximately 45 square miles) of the protected area to bottom trawling.

Why is Greenpeace targeting the North Sea?

Bottom trawling involves fishing vessels dragging large, weighted nets across the seabed to catch fish. The method can damage sensitive underwater habitats, including corals, sponges and seagrass beds, while disturbing marine ecosystems and affecting species that depend on them. According to Greenpeace UK, bottom-towed fishing gear was used for at least 37,200 hours in the Southern North Sea protected area in 2025, more than at any other UK offshore MPA. Despite its protected designation, much of the site does not have restrictions on bottom trawling or dredging.The organisation argues that these activities threaten the food supply and habitats of harbour porpoises, small marine mammals that inhabit the region. The animals can also become accidentally entangled in fishing nets, potentially preventing them from reaching the surface to breathe. According to the Joint Nature Conservation Committee (JNCC), the Southern North Sea site is particularly important for harbour porpoises, supporting approximately 17.5% of the UK North Sea management-unit population.“With no restrictions on bottom trawling, the harbour porpoise – supposedly ‘protected’ in these waters – instead faces a barrage of daily threats. This includes the immediate threat of death by bycatch, noise pollution, weakened visibility, habitat destruction, and critically, the mass depletion of the prey these mammals rely on for feeding and survival,” Greenpeace said in a statement.

Why activists took direct action

Will McCallum, Greenpeace UK’s co-executive director, said the organisation had warned the government in June that it would take direct action if sufficient measures were not introduced to protect marine habitats. “Hulking great ships prowl our oceans day after day, stripping them of fish and killing precious wildlife like dolphins, sharks and sea birds. With our ship and a movement behind us, we’re doing what the government isn’t: Protecting our seas,” McCallum said.The campaigners argue that designating an area as a Marine Protected Area is not enough if destructive fishing activities are still permitted within its boundaries. Greenpeace has called on ministers to introduce stronger restrictions on bottom trawling across protected waters.The latest operation also has celebrity and political backing. Actors Simon Pegg and Benedict Cumberbatch, alongside several British public figures and MPs, signed the boulders before their deployment. The organisation said the signatures represented their support for stronger protection of marine ecosystems. Greenpeace also plans to patrol the area using the Arctic Sunrise in the coming days, aiming to discourage industrial fishing vessels from operating around the boulder placements.

Did Greenpeace have permission to drop the boulders?

The operation has raised questions about whether environmental activists can independently place objects on the seabed to prevent commercial fishing. Greenpeace has acknowledged that it did not obtain a marine licence before deploying the boulders, describing the move as a last resort after years of unsuccessful attempts to persuade the government to introduce stronger protections.Under Sections 65 and 66 of the UK’s Marine and Coastal Access Act 2009, depositing a substance or object in the sea or on the seabed from a vessel is generally considered a licensable marine activity. Such activities require permission from the appropriate licensing authority unless a relevant exemption applies.The Marine Management Organisation (MMO), which oversees marine licensing in England, has not announced a specific enforcement outcome in its published notice about the latest deployment. However, the absence of a licence means the operation should not be described as officially authorised.Following the deployment, the MMO published the nine reported boulder positions on November 2, after Greenpeace relayed their coordinates to HM Coastguard. The regulator said the information was being shared to help fishing vessels and other sea users navigate the area safely. The MMO also clarified that it had not independently verified all the coordinates and advised mariners to take the reported positions into account when planning and conducting their activities.The UK government has also defended its broader marine protection framework. According to reporting by The Guardian, a government spokesperson said that legislation already protects marine sites, that damaging fishing activities have been banned in more than 100 locations and that further restrictions are being considered. The government also stressed that activities at sea must be conducted lawfully and safely.