UK Fighter Jet Purchase Could Breach Nuclear Treaty, Warns CND

Published: 26 September 2025, The English Chronicle Desk

Britain risks violating its international nuclear disarmament obligations if Labour proceeds with the £1 billion acquisition of 12 F-35A fighter jets, according to a legal opinion commissioned by the Campaign for Nuclear Disarmament (CND). The report, authored by two international law specialists, argues that the planned reintroduction of air-launched nuclear weapons for the Royal Air Force (RAF) would breach the United Kingdom’s commitments under the Nuclear Non-Proliferation Treaty (NPT).

Prof Christine Chinkin and Dr Louise Arimatsu of the London School of Economics concluded that the UK would contravene Article Six of the NPT, which obliges signatories to pursue negotiations in good faith toward the cessation of the nuclear arms race and to work toward general and complete disarmament. The lawyers suggested that the government’s decision to purchase F-35As specifically for their nuclear capabilities undermines the UK’s long-standing commitment to disarmament.

“The decision of the UK to purchase F-35A fighter jets rather than any other model is precisely because the aircraft can ‘deliver both conventional and nuclear weapons’ and thereby enable the RAF to reacquire ‘a nuclear role for the first time since 1998,’” the authors wrote. “Reinstating a nuclear role for the RAF represents a reversal of the UK’s long-term commitment to nuclear disarmament, including under the NPT.”

The opinion highlights a growing tension between international treaty obligations and a broader global trend of nuclear rearmament. Keir Starmer announced in June, at a NATO summit, that the UK would acquire 12 F-35As as part of its contribution to the alliance’s nuclear mission. The aircraft would be capable of deploying US B61-12 nuclear bombs stored at RAF Lakenheath in Suffolk in the event of a major conflict.

The move comes four years after the UK government lifted the cap on its Trident submarine-launched nuclear warheads, increasing the stockpile by 40% to 260. This marked the first expansion of Britain’s nuclear capability since the end of the Cold War and underscored the country’s renewed focus on deterrence.

Sophie Bolt, general secretary of CND, accused the government of “yet another breach of international law” and warned that the purchase would escalate global nuclear risks. She urged MPs to debate Britain’s nuclear intentions, noting that the F-35A procurement plan had been announced “without parliamentary debate or scrutiny.”

The Ministry of Defence defended the purchase, stating that the new F-35As would strengthen the UK’s national security. A spokesperson emphasized that Britain remains “committed to the goal of a world without nuclear weapons and upholds all our obligations under the nuclear non-proliferation treaty.”

The context of rising international tensions reinforces the urgency of the debate. In July, the United States deployed additional B61-12 bombs to RAF Lakenheath, while Russia has moved nuclear missiles to Belarus. China continues to expand its nuclear arsenal by approximately 100 warheads annually, aiming for 1,500 by 2035, according to the Stockholm International Peace Research Institute.

The NPT, which entered into force in 1970, has been signed by 190 countries, including the world’s major nuclear powers: the US, Russia, China, France, and the UK. Article Six, a cornerstone of the treaty, commits signatories to pursue disarmament negotiations in good faith. A small number of countries, such as Israel, India, and Pakistan, never joined, while North Korea withdrew in 2003.

The legal opinion and growing public scrutiny reflect a wider debate about Britain’s nuclear policy. While the government maintains that the purchase of F-35As is a defensive measure, critics argue it represents a step back from disarmament commitments and risks contributing to an increasingly volatile global security environment.

The decision will likely feature prominently in political discussions in the coming months, particularly during the ongoing Labour conference, as MPs, experts, and campaigners weigh the implications of Britain’s nuclear strategy for both national security and international law.