Britain’s F-35 Programme: Ambition Squandered, Carriers Starved, and Too Little, Too Late
By Mark Allatt, UK Defence First
The United Kingdom entered the F-35 Lightning II programme as a Tier 1 partner with high hopes and a clear strategic vision. In the mid-2000s the plan was ambitious yet coherent: 138 short take-off and vertical landing F-35Bs would equip both the Royal Air Force and the Fleet Air Arm. These aircraft would restore fixed-wing carrier strike after the Harrier’s premature retirement and give the two Queen Elizabeth-class carriers the potent air wing they were designed to operate. Two decades later the picture is one of chronic delay, diluted ambition and capability shortfalls. Forty-eight aircraft have been delivered, one has been lost, the next order of twenty-seven has been slowed and partly diverted to land-based F-35As, weapons integration remains years behind schedule, and the numbers available fall far short of what is needed to use the carriers to their full potential. As past UK Defence First commentary on the F-35, the Fleet Air Arm and Royal Navy funding has repeatedly warned, this is a classic case of all too little, too late.
The original commitment to 138 aircraft was reaffirmed as recently as the 2015 Strategic Defence and Security Review. That figure was intended to provide sufficient mass for concurrent operations, training, maintenance and surge deployments of around twenty-four jets per carrier. Reality proved far more constrained. Successive reviews, austerity and competing priorities reduced the first firm order to just forty-eight F-35Bs. Deliveries, which began in 2012, crawled forward. The final aircraft of that tranche only arrived in March or April 2026. One jet was written off after a mishap on HMS Queen Elizabeth in November 2021, leaving the Lightning Force with forty-seven airframes. The National Audit Office has documented persistent shortfalls in spares, engineers and flying hours. Mission-capable rates have hovered at roughly half the Ministry of Defence’s target, with full mission capability closer to one-third. On a typical day only ten or eleven aircraft are flyable and five or six are fully combat-ready.
Against this backdrop the decision, announced in June 2025, to switch twelve of the next twenty-seven aircraft from F-35B to F-35A is particularly damaging. The F-35As are intended to join NATO’s dual-capable aircraft nuclear mission, carrying United States B61-12 gravity bombs. The government claims a unit cost saving of up to 25 per cent and presents the move as a strengthening of the UK’s nuclear posture. Yet the operational opportunity cost is severe. Every F-35A is an aircraft that cannot operate from the Queen Elizabeth-class carriers. The switch reduces the planned second-tranche B force from twenty-seven to fifteen, leaving a projected total of around sixty-two F-35Bs by the early 2030s. A mixed fleet introduces separate logistics chains, training pipelines, infrastructure and sustainment costs. As Navy Lookout and UK Defence First analysis have highlighted, this dilutes the carrier-capable pool precisely when the Fleet Air Arm most needs depth. The nuclear role itself is of questionable utility for a medium power already possessing continuous at-sea deterrence; free-fall bombs delivered by a non-stealth-optimised profile in a high-threat environment look like a political gesture rather than a decisive capability.
Worse still, the order for those twenty-seven aircraft has itself been slowed. As the UK Defence Journal has reported, firm details and contractual commitment await the long-delayed Defence Investment Plan. What was once expected as a coherent follow-on batch before the end of the decade remains frozen. Without an approved timetable the gap between the original 138 ambition and the contracted force continues to widen. Production lines for the B variant face eventual closure pressure, and early low-rate airframes may retire before later ones arrive, further eroding numbers.
A stark contrast with Italy and Japan
The UK’s hesitant approach stands in sharp relief when set against other F-35B operators, particularly Italy and Japan. Italy, a Level 2 partner, has pursued a more balanced and steadily expanding programme. After early cuts from an ambitious original plan, Rome settled on a force that now includes around 75 F-35As and 40 F-35Bs. Crucially, both the Italian Air Force and Navy operate the B variant, with the latter embarking them on the carrier Cavour. Italy also hosts the European final assembly and check-out facility at Cameri, giving it industrial depth and a degree of sovereign production. Deliveries have proceeded with less drama than in Britain, and recent decisions have actually added further aircraft rather than diverting or delaying them. The result is a growing dual-service fleet that supports both land-based and maritime operations without the self-inflicted complications of a late switch to a non-carrier variant.
Japan provides an even more telling comparison. Tokyo has committed to 147 F-35s in total - 105 F-35As and 42 F-35Bs - making it the largest operator outside the United States once deliveries complete. The 42 B models are specifically intended for the converted Izumo-class multi-purpose destroyers, which are being transformed into light aircraft carriers capable of STOVL operations. Japan has already begun receiving its first F-35Bs, with more arriving through 2026, and has successfully conducted trials with both American and British F-35Bs on its decks. This represents the restoration of fixed-wing carrier aviation for Japan for the first time since the Second World War - a decisive, capability-driven investment made in response to the regional threat environment. While Japan’s carriers are smaller than the Queen Elizabeth class, the country is matching platforms with aircraft in a coherent, accelerated fashion rather than diluting its STOVL force for political or short-term budgetary reasons.
Both nations demonstrate what focused procurement looks like: clear prioritisation of the maritime role where it matters, industrial engagement that reinforces rather than substitutes for operational numbers, and a willingness to fund the aircraft needed to make expensive ships useful. Britain, by contrast, has the largest and most capable STOVL carriers in Europe yet is starving them of the very aircraft they require, while diverting scarce resources into a small fleet of nuclear-capable F-35As that cannot fly from those decks.
Weapons integration forms another critical failure. The F-35B still lacks the MBDA Meteor beyond-visual-range air-to-air missile and the SPEAR 3 precision strike weapon. Both were supposed to arrive far earlier; full operational capability is now pushed into the early 2030s, dependent on the troubled Technology Refresh 3 and Block 4 software releases. In the meantime British jets rely on AMRAAM and free-fall or laser-guided bombs. The absence of a true stand-off air-to-surface weapon leaves the force vulnerable in contested environments. Interim purchases such as StormBreaker admit the shortfall but do not restore sovereign deep-strike reach. This is not merely a technical delay; it is a fundamental limitation on the combat utility of an aircraft bought for high-end operations. Other partners face similar Block 4 timelines, yet the UK’s smaller fleet and lower availability amplify the impact of every delay.
The cumulative effect is that the UK cannot use its two large carriers to anything approaching their full potential. The Queen Elizabeth class was designed around an air wing of twenty-four or more F-35Bs, with theoretical capacity for thirty-six. Sustaining that number across two hulls, while meeting training, regeneration and concurrent commitments, requires a healthy fleet well north of sixty or seventy aircraft, plus adequate spares and people. Current availability makes even a single twenty-four-jet deployment a major strain, as demonstrated during recent Carrier Strike Group operations. The Fleet Air Arm, whose revival was one of the programme’s original justifications, remains a junior partner in a joint force dominated by RAF priorities and chronically short of the mass needed for independent maritime power projection. Past UK Defence First pieces on Royal Navy funding have repeatedly stressed that carriers without sufficient aircraft, weapons and support are expensive prestige projects rather than credible warfighting tools. The same pattern of under-investment that leaves the surface fleet short of escorts and the submarine service overstretched now afflicts carrier aviation.
Industry has derived substantial benefit from the programme, with British firms contributing around 15 per cent by value of every F-35 produced worldwide. That industrial return is real, yet it does not compensate for operational hollowness. The whole-life cost of even the limited fleet is ballooning well beyond early estimates, while the capability delivered remains constrained by numbers, readiness and armament. Italy’s Cameri facility and Japan’s expanding programme show that industrial participation can coexist with robust force structure; Britain has allowed the industrial story to obscure the operational one.
In sum, Britain has spent more than a decade and many billions of pounds to field a fifth-generation force that is still too small, too poorly armed and too fragile to realise the promise of the Queen Elizabeth-class carriers. The original 138-aircraft vision has been reduced first to forty-eight, then diluted by the F-35A diversion, and now slowed by bureaucratic delay. Weapons that should already be in service remain years away. Allies such as Italy and especially Japan are building larger, more coherent F-35B fleets tailored to their maritime needs, while the UK - possessing the most capable STOVL carriers of any partner - continues to under-deliver. The Fleet Air Arm and the Royal Navy’s carrier strike ambition are left under-resourced at precisely the moment peer competition demands credible mass and lethality. Successive governments have preferred incrementalism and presentational announcements over the hard choices required to match platforms with aircraft, weapons and people. The result is all too little, too late. Unless the forthcoming Defence Investment Plan reverses course with a firm, accelerated order for additional F-35Bs and prioritised weapons integration, the United Kingdom risks possessing two of the world’s most capable aircraft carriers that it cannot properly fight.