The United Kingdom’s surprising decision to buy a dozen conventional takeoff and landing (CTOL) F-35A fighters has taken another turn. According to a U.K. Royal Air Force official, “We did not buy those aircraft for their dual [nuclear] capability, we bought them for our conversion unit. At the same time, we stated we would get back into the [nuclear] role supporting NATO. The two are separate functions.”
The official was speaking today at the Global Air & Space Chiefs’ Conference in London. Events of this kind are typically conducted under Chatham House rules, meaning that information can be freely shared with the public, but the identity of the speakers cannot be disclosed. Their words were reported by Gareth Jennings, aviation desk editor at Janes.
As you can read about here, the United Kingdom announced in June last year that it would buy 12 F-35As alongside the short takeoff and vertical landing (STOVL) F-35B models it already uses.
At that point, the U.K. Ministry of Defense specifically highlighted the F-35A’s ability to join the NATO nuclear mission, which would see the jets armed with U.S.-owned B61-12 nuclear gravity bombs. The F-35B, with its smaller weapons bays, is not able to carry these weapons.
“The U.K. will purchase 12 new F-35A fighter jets and join NATO’s dual-capable aircraft nuclear mission in a major boost for national security,” the U.K. Ministry of Defense announced. The ministry described this as the “biggest strengthening of the U.K.’s nuclear posture in a generation, complementing the U.K.’s existing sea-borne deterrent.”
Earlier in June 2025, the Strategic Defense Review, published by the U.K. Ministry of Defense, had suggested that the future Lightning Force could comprise a mix of F-35As and F-35Bs.
At the same time, however, the Royal Air Force had noted that the F-35As would be assigned to a training unit and would primarily be used in that role.
As the F-35A is cheaper to operate, it is considered a better option to use for training sorties, including keeping pilots current on the F-35B. The ministry said buying the 12 jets will bring a saving of 25 percent per aircraft over the F-35B.
“Day-to-day, the F-35As will be used in a training role on 207 Squadron, the Operational Conversion Unit (OCU),” the Royal Air Force said. “As the F-35A carries more fuel than the F-35B variant, it can stay airborne for longer, extending the available training time in each sortie for student pilots. As F-35As also require fewer maintenance hours, there will be increased aircraft availability on the OCU. These factors combined will improve pilot training and reduce the amount of time for pilots to reach the frontline squadrons.”
The tradeoff is that the F-35A can’t be used to train for STOVL missions, but this part of the F-35B profile can be trained in the simulator, while an F-35A training unit frees up more F-35Bs to deploy aboard the two Queen Elizabeth class aircraft carriers.
Now, the words of the Royal Air Force official today cast doubt on whether the F-35As will actually take on the nuclear strike role, something that was specifically highlighted in the U.K. Defense Investment Plan published last month.
As well as today’s underscoring of the priority of the training mission, it should be noted that the new F-35As will be based at RAF Marham, in eastern England, and it’s unclear whether the airfield retains the underground weapons vaults for nuclear bombs. Some reports suggest the vaults that existed there in the Cold War have been dismantled or even filled in completely. In the past, we speculated that the jets might have to make use of nearby RAF Lakenheath, where there is evidence that the United States has brought nuclear bombs back to the United Kingdom, for its own use.
At the same time, as we have explained in the past, while the nuclear-sharing program provides access to U.S.-owned weapons, it still requires the United States and NATO to approve their use.
U.K.-operated nuclear-capable F-35As would not offer the same sovereign capability as the Royal Navy’s ballistic missile submarines, around which the British nuclear deterrent is based.
Then there is the issue of how much training, and other resources, would have to be assigned to the nuclear mission to ensure that it could actually be executed. Certainly, this would be nothing like the Cold War era, when a handful of jets stood fully armed, round the clock, on each assigned RAF base, with their crews waiting for the alert to sound.
The reality would likely involve the unit switching to focusing on the nuclear mission in times of crisis. This raises a question about how long this would take, and to what degree it would provide a real deterrent, bearing in mind the need to spin it up to be combat-ready.
These are all questions we have asked before in relation to the U.K. F-35A’s proposed nuclear role.
Now, the Royal Air Force itself is dialing back expectations in this regard.
Ultimately, the best chance of the Royal Air Force having a meaningful dual-role nuclear mission would be to buy more F-35As. As it stands, the 12 F-35As are part of the core buy, not additional to it.
The U.K. Ministry of Defense has long said that it still expects to procure 138 F-35s over the lifetime of the program. So far, 48 F-35Bs have been delivered, and the government is committed to buying 15 more F-35Bs and the 12 F-35As for delivery by 2033.
The lack of numbers has seen the United Kingdom rely on U.S. Marine Corps F-35Bs to make up the required aircraft numbers during carrier cruises.
The F-35A argument would become much more compelling, and more cost-effective, if it were to be bought in larger numbers.
The F-35A is more capable in general, with superior range and payload, and it can maneuver at 9G, while the F-35B is cleared for 7.5G.
One unresolved issue as far as the British are concerned is the F-35A’s refueling receptacle, which is incompatible with their fleet of Voyager tankers. Modifications could provide the British F-35A with a probe, but would likely only make sense on the back of a bigger buy.
While many senior Royal Air Force officers might favor getting more F-35As, the jet is now also competing with the Global Combat Air Program (GCAP), at the center of which is the Tempest crewed stealth fighter, as well as emerging drone programs.
In the meantime, the British are struggling to find money for more basic elements of the F-35B, which still critically lacks a standoff strike capability. A report late last year found that a history of “cost-cutting” throughout the U.K. F-35 program “has caused significant problems in its use,” which have affected the jet’s “capability, availability to fly, and value for money.”
The U.K. Ministry of Defense also needs to spend more than $83 billion over the next four years to fund its nuclear-powered submarine programs, which include a true sovereign nuclear capability of the kind that the F-35A is unable to provide.
Contact the author: thomas@thewarzone.com