Source · Select Committees · Public Accounts Committee
51st Report - The UK’s F-35 stealth fighter capability
Public Accounts Committee
HC 1232
Published 31 October 2025
Recommendations
2
Accepted
Set out plans to ensure F-35 standoff capability and increase aircraft availability.
Recommendation
The UK’s F-35 does not have a standoff weapon, and aircraft availability is inadequate. The Department states that its biggest concern with its F-35 fleet is the lack of a standoff weapon to strike ground targets from a safe distance. …
Read more
Government Response Summary
The government agreed to increase F-35 availability by increasing aircraft engineers, supporting efforts to improve spares availability, investing in F-35 technical infrastructure, and enhancing supporting enablers, with a full report on availability to follow later.
HM Treasury
View Details →
11
Deferred
Overall F-35 capability and availability remain inadequate, lacking standoff weapons and stealth assessment
Recommendation
Although the F-35 is significantly superior to any previous UK aircraft, the Department has yet to achieve the capability or availability that it wants.19 Most significant is the lack of the standoff weapon.20 This will limit the UK’s ability to …
Read more
Government Response Summary
The government will set out its approach to delivering the Strategic Defence Review and the investments required to deliver the Integrated Force in the forthcoming Defence Investment Plan, including details on the standoff capability requirement.
HM Treasury
View Details →
13
Deferred
Department actively pursuing solutions to F-35 limitations, accelerating weapon integration and international assessment
Recommendation
The Department told us that it had plans to tackle these limitations. It is seeking opportunities within the global programme to accelerate the integration onto the F-35 of Spear 3 and Meteor, its preferred air to air weapon. The Joint …
Read more
Government Response Summary
The government agrees with the Committee’s recommendation and states that the forthcoming Defence Investment Plan will set out the government’s approach to delivering the Strategic Defence Review (SDR) and the investments required to deliver the Integrated Force. This will provide details of the government’s balance of investment across the full range of military capabilities, including the capability requirement identified by the Committee.
HM Treasury
View Details →
15
Rejected
F-35 programme plagued by critical shortages of engineers, pilots, and flying instructors
Recommendation
The F-35 programme suffers from personnel shortages across a range of occupations. A 2024 review of the programme, by the National Infrastructure and Service Transformation Authority (NISTA, formerly the Infrastructure and Projects Authority), stated that shortages of suitably qualified engineers …
Read more
Government Response Summary
The government disagrees with the recommendation to produce a plan specifically focused on the F-35 workforce, and will address the issue through the ongoing RAF People Campaign.
HM Treasury
View Details →
18
Deferred
F-35 personnel at RAF Marham face unacceptable, low-quality accommodation and insufficient amenities
Recommendation
RAF Marham has been designated the F-35 main operating base since 2013 and now has at least 1,500 people working at the base to support the F-35 fleet, many of whom also live there.38 A 2025 NISTA programme review found …
Read more
Government Response Summary
Following the publication of the Defence Investment Plan infrastructure requirements will be reassessed against departmental priorities. The department will write to the Committee by 31 May 2026 to advise whether the current timescale for RAF Marham accommodation can be brought forward.
HM Treasury
View Details →
21
Deferred
Accelerate the unacceptable 13-year accommodation upgrade programme at RAF Marham
Recommendation
The Department told us that it has plans to upgrade accommodation at RAF Marham but will not complete these plans for many years. The Department will upgrade 900 accommodation units and bedrooms across the base. However, the Department told us …
Read more
Government Response Summary
The Department will reassess infrastructure requirements against departmental priorities following the publication of the Defence Investment Plan, and will advise the Committee by 31 May 2026 whether the timescale for RAF Marham accommodation can be brought forward.
HM Treasury
View Details →
27
Accepted
Department's F-35 whole-life cost approach hinders sound long-term financial management
Recommendation
The Department told us that its approach to whole-life costs gave it the right cost information for the management decisions it needs to make. It argued that coming up with a whole life cost out to 2069 was not helpful …
Read more
Government Response Summary
The department will continue to strengthen its approach to whole life cost modelling as part of the work that is being taken forward under Defence Reform. The department already develops whole life cost models that extend beyond equipment costs, for example covering personnel and infrastructure costs too, but accepts that there is an opportunity to go further in developing and presenting a fuller and more complete view of through-life cost.
HM Treasury
View Details →
Conclusions (23)
3
Conclusion
Rejected
The F-35 programme faces an unacceptable shortage of several types of personnel, including engineers, cyber specialists, pilots and qualified flying instructors. The Department acknowledges that there are significant shortages of engineers in the F-35 programme, and that this is an impediment to operating the aircraft more often. This shortage reflects …
Government Response Summary
The government rejected the recommendation for a specific F-35 workforce plan, stating it will address recruitment and retention challenges through the ongoing RAF People Campaign and by continuing existing initiatives like financial incentives and recruitment policy adjustments.
4
Conclusion
Acknowledged
Accommodation at RAF Marham is substandard, exacerbating issues with recruitment and retention. Despite the urgent need to address this, upgrades will not be completed under current plans until 2034. RAF Marham has been the main F-35 operating base since 2013, with at least 1,500 people working there on the F-35, …
Government Response Summary
The government agreed to prioritize improvements to RAF Marham accommodation and committed to reassessing the current timescale against departmental priorities, writing to the Committee by May 2026 to advise if the completion date can be brought forward.
5
Conclusion
Acknowledged
The Department has taken a narrow and short-term approach to management and costs and has failed to realistically appraise the programme’s whole-life cost. The Department acknowledges that it reduced the pace of aircraft deliveries to make short-term financial savings at multiple points in the programme, notably in 2010. In 2021 …
Government Response Summary
The government agreed to include all non-equipment costs in whole-life cost forecasts, stating it already develops such models but accepts there is an opportunity to go further and will strengthen its approach as part of Defence Reform.
6
Conclusion
Rejected
The Department has not set out its preferred mix of F-35As and Bs, nor forecast the costs of introducing the F-35As in their nuclear weapons role. The 48 aircraft that the Department has contracted for so far are all F-35Bs, which can be flown from land or aircraft carriers. In …
Government Response Summary
The government rejected the recommendation to provide an update on additional whole-life costs and timescales for operating Dual Capable Aircraft, stating that this information is classified Secret but offered a classified briefing to the Committee.
1
Conclusion
Acknowledged
On the basis of a report by the Comptroller and Auditor General, we took evidence from the Ministry of Defence (the Department) on its oversight and management of the UK’s F-35 fighter programme.1
Government Response Summary
The government agreed with the committee's implicit recommendation on oversight, stating it will continue to strengthen its approach to defining and approving capability entry-into-service criteria and declaring service entry for new capabilities as part of Defence Reform.
7
Conclusion
Deferred
The Department expects to declare Full Operating Capability (FOC) by the end of 2025. In its 2018 Concept of Use document the Department had expected to declare FOC by the end of 2023 based on two frontline squadrons of 12 aircraft and a training squadron at full capacity. It subsequently …
Government Response Summary
The government response is entirely unrelated to the recommendation regarding the F-35 Full Operating Capability (FOC) declaration, instead discussing the 'illegal meat crisis' and biosecurity at the border.
8
Conclusion
Deferred
The Department told us that its criteria for declaring FOC are based on a combination of hard facts and applied military judgement. In forming its view, it told us that it had considered FOC through four distinct 5 C&AG’s Report, para 9 6 Q 91 7 C&AG’s Report, para 1.19 …
Government Response Summary
The government response is entirely unrelated to the recommendation regarding the F-35 Full Operating Capability (FOC) criteria, instead discussing animal vaccine availability and ongoing cross-sector engagement, with an action plan to be published in late 2026.
9
Conclusion
Deferred
The Department acknowledged that its definition of FOC excludes a crucial element of capability. It does not include a requirement to integrate Spear 3 onto the F-35 to provide a standoff weapon to attack ground targets from a safe distance, which it does not expect to have until the early …
Government Response Summary
The government response is entirely unrelated to the recommendation regarding the F-35 FOC definition, Spear 3 integration, or personnel shortages, instead discussing Sanitary and Phytosanitary (SPS) agreements with the EU and strengthening resilience to animal disease.
10
Conclusion
Acknowledged
The Department also told us that the 2025 CSG deployment, required for FOC declaration, had impacted availability before the deployment and would impact availability for some weeks after the deployment, because of the need for additional maintenance.16 The National Audit Office’s report noted that the impact of the deployment on …
Government Response Summary
The department acknowledges the factors affecting aircraft availability and is increasing the number of aircraft engineers, supporting the US-led F-35 Joint Programme Office, and planning further investments in F-35 technical infrastructure.
12
Conclusion
Deferred
The Department set out why these capability limitations have occurred. It told us that its ability to integrate new weapons was dependent on the global F-35 programme run by the United States Department of Defense. It requires the major software enhancements provided by Tech Refresh 3 and Block 4, which …
Government Response Summary
The government will set out its approach to delivering the Strategic Defence Review and the investments required to deliver the Integrated Force in the forthcoming Defence Investment Plan, including details on the standoff capability requirement.
14
Conclusion
Acknowledged
The Department also set out the reasons for poor availability of aircraft. It accepted that shortages of personnel, particularly engineers, impacted aircraft availability, and would continue to do so until they were resolved.30 Furthermore, the Department told us that the Global Support Solution, which supplies spare parts, is being reset …
Government Response Summary
The department is increasing the number of aircraft engineers to align with Force readiness requirements, and is supporting the US-led F-35 Joint Programme Office in efforts to reset the Global Support Solution to improve performance and increase spares availability. The department is planning further investments in F-35 technical infrastructure at RAF Marham and enhancements to supporting enablers through improvement initiatives.
16
Conclusion
Rejected
The Department acknowledged that the shortages across all these roles were very important, with the Chief of the Defence Staff stating that personnel had been one of his top two priorities in his previous role as Chief of the Air Staff. The Department told us that the training time required …
Government Response Summary
The government disagrees with the recommendation to produce a plan specifically focused on the F-35 workforce, and will address the issue through the ongoing RAF People Campaign.
17
Conclusion
Rejected
The Department told us that it has plans in place to fix its recruitment and retention problems. The Department also told us that it has increased its recruitment of engineers significantly in the last two years. It has offered joining bonuses for certain professions and has increased the capacity of …
Government Response Summary
The government disagrees with the recommendation to produce a plan specifically focused on the F-35 workforce, and will instead address recruitment and retention challenges through the ongoing RAF People Campaign. They also outlined a range of measures already introduced to address immediate pressures, particularly for some specialist areas, including financial retention incentives and increased opportunities for Extensions of Service.
19
Conclusion
Deferred
The Department accepted that accommodation at RAF Marham is not good enough, reflecting wider problems within the Defence estate, more than half of which is over 50 years old. The Department told us that it had identified the need for increased investment in accommodation in the Strategic Defence Review and …
Government Response Summary
The government agrees with the recommendation, but will reassess infrastructure requirements against departmental priorities following the publication of the Defence Investment Plan and will advise the Committee by 31 May 2026 whether the current timescale for RAF Marham accommodation can be brought forward.
20
Conclusion
Deferred
The Department acknowledged that providing poor quality accommodation negatively impacts its personnel. Most significantly, it increases the risk that people leave the service earlier than they otherwise would.41 This is a serious risk given the problems with retention that the Department has set out and the length of time it …
Government Response Summary
The government agrees with the recommendation, but will reassess infrastructure requirements against departmental priorities following the publication of the Defence Investment Plan and will advise the Committee by 31 May 2026 whether the current timescale for RAF Marham accommodation can be brought forward.
22
Conclusion
Deferred
The Department acknowledged that it has, on occasion, prioritised short-term affordability over value for money in the F-35 programme, to keep within its overall departmental budget.46 Notably, in 2021 the Department took the decision to delay investment in the Air Signature Assessment Facility (ASAF). Although this decision saved £82 million …
Government Response Summary
The government agrees with the Committee’s recommendation and states that as part of the production of the forthcoming Defence Investment Plan, the government is considering the long-term impacts of any savings measures on costs and capability of all major programmes.
23
Conclusion
Deferred
In correspondence provided after our evidence session the Department told us that 809 Naval Air Squadron’s infrastructure is another example of short-term savings resulting in higher overall costs. In 2020 the Department forecast that the cost of building the infrastructure would be around £56 million and be completed in 2023. …
Government Response Summary
The government agrees with the Committee’s recommendation and states that as part of the production of the forthcoming Defence Investment Plan, the government is considering the long-term impacts of any savings measures on costs and capability of all major programmes.
24
Conclusion
Deferred
The Department also acknowledged that short-term savings impact the capability provided by the programme. The ASAF, which measures the stealth characteristics of the UK F-35 fleet, is needed for the Department’s freedom of action policy so that it can deploy the aircraft at any time or place of its choosing.49 …
Government Response Summary
The government agrees with the Committee’s recommendation and states that as part of the production of the forthcoming Defence Investment Plan, the government is considering the long-term impacts of any savings measures on costs and capability of all major programmes.
25
Conclusion
Deferred
The Department told us that in 2010, facing a reduction in its budget, it chose to delay the delivery of some aircraft.52 This has reduced the number of aircraft available to the Department today.53 This was exacerbated by a further delay of seven aircraft by a year in 2020 for …
Government Response Summary
The government is considering the long-term impacts of savings measures on costs and capability of all major programmes as part of the production of the forthcoming Defence Investment Plan.
26
Conclusion
Acknowledged
In 2013 the Department set out a whole-life cost for the F-35 programme of £18.4 billion, although this only covered the first 48 aircraft out of the 138 that the UK has announced it intends to buy. Before the publication of the National Audit Office report in 2025 this figure …
Government Response Summary
The department will continue to strengthen its approach to whole life cost modelling as part of the work that is being taken forward under Defence Reform. The department already develops whole life cost models that extend beyond equipment costs, for example covering personnel and infrastructure costs too, but accepts that there is an opportunity to go further in developing and presenting a fuller and more complete view of through-life cost.
28
Conclusion
Rejected
The Department is deciding what mix of the two F-35 variants to buy in its procurement process. In Phase 1 the UK has contracted for 48 F-35Bs, which can fly from land bases and aircraft carriers. In June 2025 the Department announced its intention to buy 12 F35As, which cannot …
Government Response Summary
The government disagrees with the Committee’s recommendation. Costs and timescales associated with the UK's Dual Capable Aircraft nuclear mission are classified Secret.
29
Conclusion
Rejected
The Department told us why it had decided to purchase some A variants. The A variant can fly further for longer than the B variant, because it does not have the weight limitations that come with the ability of the B variant to do short take-off and landing on aircraft …
Government Response Summary
The government disagrees with the Committee’s recommendation. Costs and timescales associated with the UK's Dual Capable Aircraft nuclear mission are classified Secret.
30
Conclusion
Rejected
The Department explained that it is starting to understand the practical requirements of becoming certified for the NATO nuclear mission. The Department needs to meet standards for handling, loading and using nuclear weapons. These standards are set by the United States since it provides the weapons, and the Department is …
Government Response Summary
The government disagrees with the Committee’s recommendation, but offers a briefing at Secret level following the Defence Investment Plan publication.