Radioactive Leak at UK’s Nuclear Warhead Base Sparks Outcry Over Safety and Secrecy

Published: 09 August 2025. The English Chronicle Desk

Radioactive water from one of the United Kingdom’s most sensitive military sites — the armaments depot at Coulport, which stores the nation’s nuclear warheads — has leaked into a Scottish sea loch after years of neglected maintenance, according to official files newly released following a prolonged legal battle.

The confidential reports, compiled by the Scottish Environment Protection Agency (Sepa) and only recently made public, reveal that old and poorly maintained water pipes at the Coulport facility repeatedly burst, releasing polluted water into Loch Long, a sea loch west of Glasgow. The base holds the Royal Navy’s stockpile of nuclear warheads for its fleet of four Vanguard-class submarines, each armed with Trident missiles, and is regarded as one of the most secure and secretive sites in the country.

The leaks, Sepa found, were the result of “shortfalls in maintenance” across a sprawling network of 1,500 pipes, with up to half of the components beyond their design life at the time of the incidents. These failings caused unnecessary releases of low levels of tritium — a radioactive isotope used in nuclear warheads — into the surrounding waters. While the detected levels were reportedly too low to pose a direct risk to human health, environmental watchdogs have condemned the lack of preventative measures and the Ministry of Defence’s repeated delays in addressing the problem.

The files also expose a history of pipe bursts at the site, including one in 2010, two in 2019, and a series of further failures in 2021. A particularly serious incident in August 2019 flooded a nuclear weapons processing area, contaminating water that then passed through an open drain into Loch Long. Despite promises from the MoD in 2020 to carry out 23 remedial actions, Sepa inspections in 2022 found that progress was “slow and delayed in many cases,” with further maintenance failings emerging.

David Cullen, a nuclear weapons policy expert with the London-based think tank Basic, described the revelations as “shocking” and accused the MoD of “outrageous” secrecy. He noted that the leaks occurred despite an ongoing £2 billion infrastructure programme at Coulport and the nearby Faslane naval base. “This negligent approach is far too common in the nuclear weapons programme,” he said, “and is a direct consequence of a lack of oversight.”

The reports, which were initially withheld by both Sepa and the MoD on national security grounds, were released only after a six-year freedom of information battle led by investigative journalists. Scottish information commissioner David Hamilton ordered disclosure, ruling that the files threatened reputations rather than national security. The MoD sought further delays, citing additional “security considerations,” but was eventually compelled to comply.

Coulport, exempt from civilian environmental regulation because of its military status, operates under a voluntary agreement with Sepa to match civilian pollution control standards. Sepa says it is now “satisfied” that substantial improvements have been made in asset management and maintenance, and that no repeat incidents have occurred since.

The MoD has maintained that there have been “no unsafe releases of radioactive material” and that it places “the utmost importance” on handling such substances securely. Nevertheless, critics argue that the revelations expose deep flaws in the UK’s nuclear weapons infrastructure, as well as a troubling willingness to shield operational failings from public view.