The UK has decided to acquire at least 12 F-35A stealth fighters. These fighter jets should be able to carry out nuclear and conventional strikes from the air, a capability the Royal Air Force (RAF) has lacked since the 1990s. The deal also marks a significant move for the UK's participation in Nato operations amid rising nuclear rhetoric from adversaries.
Author
- Arun Dawson
PhD Candidate, Department of War Studies, King's College London
The F-35A brings notable advantages over the F-35B variant already in RAF service. It's less expensive to buy and operate, has greater range - 679 miles (1093km) vs 517 miles (833km) - and supports a broader variety of weapons, including the nuclear-capable B61 bomb (with US agreement). Because it can spend longer in the air, it may also allow prospective RAF pilots to get through their pilot training quicker.
Yet while the F-35A offers greater range than many comparable fighter jets, it still requires in-flight refuelling to operate effectively over extended distances and to return home from such missions. This exposes a critical vulnerability that has been largely overlooked in public commentary: the RAF has no tanker aircraft capable of supporting the F-35A in this way. As a result, these fighter jets - carrying nuclear ordnance or otherwise - are limited in the types of operations they can carry out.
Unlike the F-35B which is compatible with the UK's current fleet of tankers, the A-model depends exclusively on "flying boom" refuelling. Flying boom is one of two aerial refuelling methods. Favoured by the United States Air Force, it uses a rigid, extendable tube to deliver fuel at a high transfer rate and is generally easier for receiving pilots to operate.
The alternative is probe-and-drogue which relies on a flexible hose and basket, connected to a probe on the receiving aircraft. While slower and more demanding to operate, it allows multiple fighters to refuel simultaneously, offers redundancy (backup options) and is simpler to integrate.
The RAF's refuelling predicament stems from an exclusive leasing deal negotiated under the last Labour government, which supplied only probe-and-drogue Voyager tankers. Although the aircraft were designed to support both systems, the UK opted not to include booms due to cost constraints and limited demand at the time.
Since then, however, the UK has steadily acquired more American-made aircraft that can only use the flying boom method to refuel: the C-17 Globemaster (air transport), RC-135W Rivet Joint (intelligence), E-7 Wedgetail (airborne command and control) and P-8A Poseidon (maritime patrol).
The F-35A announcement continues this trend but with greater implications. While the aircraft can carry external fuel tanks to extend its range, this degrades its stealth capability. Stealth means it is less easy for enemy sensors - like radar - to detect. The F-35A needs this stealth capability for nuclear missions that require penetration of contested airspace to deliver unguided B61 bombs.
The outcome is that Britain's F-35As, along with alternative and otherwise highly capable aircraft, will not be ablew to operate independently during critical military operations. London to Eastern Europe, for instance, is roughly 1,150 miles (1,852km): nearly double the distance the F-35A can fly without refuelling. Without flying boom tankers or bases in foreign countries for refuelling, tactical flexibility is compromised.
This shortfall imposes a growing reliance on allied tanker support. In crisis conditions, UK aircraft could be confined to American-led operations where such tankers exist.
This risk was manageable in previous decades; the possibility of operating without the Americans considered remote. But as the 2025 Strategic Defence Review concedes, the United States is clear that the "security of Europe is no longer its primary international focus".
And while some Nato allies in Europe as well as Australia are increasing their flying boom capacity through a multinational fleet, the UK is not as yet part of those arrangements. Retrofitting the existing Voyager fleet remains an option, but it would require an extensive - and expensive - structural overhaul, prompting the question of whether acquiring new, compatible tankers might now be a more viable path.
Either way, until Britain invests in flying boom capability or secures assured access from allies, it will have to accept constraints to its military power. Buying frontline jets is only part of the equation. Without the means to sustain them in the air, the UK risks fielding a force that can't reach its target, leaving it a spectator when it matters most.
Arun Dawson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
