Ash dieback keeps Thames island closed
The Environment Agency has warned against any planned protests over the closure of a Surrey riverside island and announced a public engagement event to update residents on safety work there.
Penton Hook Island has been shut since July 2025 after diseased trees were discovered across the site. Officials say the trees are affected by ash dieback, a disease that rots them from the inside and makes them unstable and unpredictable to cut down. As a result of the scale and complexity of the work required the island cannot safely reopen yet, officials said.
The agency has warned people not to attempt to access the island amid reports of possible protests around the site. A spokesperson said: “We would like to remind everyone that access to the island is currently prohibited due to the significant safety concerns resulting from diseased trees. Please do not attempt to access the island.”
Ash dieback weakens trees internally, meaning they can collapse or drop branches without warning. The Environment Agency said this creates a serious risk to both workers and the public, with falling branches, collapsing trunks and debris on the ground posing a potential injury hazard.
Local residents will have a chance to discuss the plans at a public engagement event on March 20, 2026, at Staines Library between 2pm and 5pm.
Environment Agency staff will provide an update on the work and hear feedback from the community. People will also be able to share information about memorials located on the island so they can be protected where it is safe to do so.
A spokesperson added: “Keeping the public safe is one of our priorities and we apologise for any inconvenience this closure may be causing. We know the importance of this site to the local community, and we are committed to keeping everyone updated on our progress.”
Instead of using standard chainsaws, specialist mechanical equipment will be needed to remove the affected trees, the Environment Agency said. The machinery will have to be transported to the island by river, adding further logistical challenges.
The agency said additional work will also be required to strengthen parts of the island bank before equipment can be brought in.
Seasonal wildlife restrictions are another factor. The bird nesting season, which runs from March to September, limits when some work can take place, further complicating the project.
Plans are also being explored to restore the island once the dangerous trees have been cleared. Environment Agency officials said they hope to replace the diseased trees with new species better suited to the island’s ecology.
Penton Hook Island – Google Maps