Background to the report

The F-35 Lightning II Joint Strike Fighter (F-35) is a technologically cutting-edge multirole stealth fighter aircraft. Originally conceived in the 1990s by the US Department of Defense, the UK is one of 8 nations that are partners in the global F‑35 programme, although the US has by far the most influence on the programme, so far ordering approximately 80% of all aircraft.

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The Ministry of Defence (MoD) began taking delivery of F-35B aircraft, a variant which can be used from land or aircraft carriers, in 2012 and has committed to purchasing 138 F‑35 aircraft, with 48 currently on contract and 38 having been received but no approved timetable for purchasing the rest. The UK’s policy is to be able to use the F‑35 at any time or place of its choosing, which it calls ‘freedom of action’.

The MoD intends to demonstrate the F-35 capability as part of a Carrier Strike Group deployment in 2025, embarking up to 24 aircraft. The MoD expects its F‑35 aircraft to remain in service until 2069 (extended from 2048).

The global programme is run by the Joint Program Office (JPO) based in Washington DC. The MoD is heavily dependent on the performance of the JPO for cost-effective delivery of the aircraft, engines and provision of support. The MoD is fully responsible for providing all other elements of capability, such as providing trained pilots, engineers and other personnel, infrastructure, weapons, and logistics. The MoD is also responsible for providing related capabilities, such as the aircraft carriers and air bases which the F‑35 is designed to fly from.

Later in June 2025, the government announced its intention to buy at least 12 F-35As capable of carrying both nuclear and conventional weapons (Dual Capable Aircraft – DCA), and that they will form part of NATO’s nuclear mission. The MoD has stated that it hopes that delivery will begin before the end of the decade.

Scope of the report

We have previously reported on the UK F-35 capability as part of our Carrier Strike reports, as well as in wider reports on MoD capability and the MoD Equipment Plan but this is our first report considering F‑35 capability in detail.

The report covers:

  • F-35 aircraft capability, delivery and availability
  • supporting enablers
  • how the MoD manages the programme and its costs  

Conclusion

The 37 F-35 aircraft now in service represent a significant improvement in the warfighting capability of the UK’s Armed Forces, with the ability to operate in high threat environments and to enhance the effectiveness of other UK defence platforms. They are in operational use, including on the current Carrier Strike Group deployment. But due to failings of both the MoD and the global programme, the level of overall UK F‑35 capability is currently lower than the MoD intended it would be by now at the time of its 2013 business case, and will be for several years.

Since 2010, MoD decisions to meet wider affordability challenges have led to delays in the delivery of aircraft and key infrastructure. The MoD has also failed to address personnel shortages and does not expect to fill gaps until 2028. And the global programme has had a series of issues which have delayed production and hindered logistical support while technology upgrade and support costs have also increased markedly over recent years.

Despite this, in recent years the MoD’s F-35 programme team has demonstrated effective day-to-day management, working collaboratively to deliver capability. Because of early and consistent commitment the UK’s position in the global programme has remained influential and contributed to UK companies earning significant contracts supplying the global programme.

In our view, the capability achieved for the estimated £11 billion spent to date is a disappointing return so far compared with MoD plans, even if other programme benefits have been significant.

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Publication details

Press release

View press release (11 Jul 2025)

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