The UK government is to buy half its target of 138 F-35 Lightning II fighter jets, according to sources close to the government’s defence review.

The Times has reported that the UK had agreed to buy 48 short take-off and vertical landing variants of the stealth multirole jets by the end of 2025 for £9.1 billion. A source said the aspiration to buy the original target amount over the lifespan of the US programme was unlikely to be fulfilled.

The 138 figure was confirmed as an ambition in the government’s defence review in 2015, but the UK is not contractually obliged to buy any more than 48. The F-35s are designed to fly from aircraft carriers with the Royal Navy’s Queen Elizabeth-class carriers expected to deploy with between 12 and 36.

A foreign policy, defence and security integrated review in ongoing and is due to conclude in November with the figure of 70 F-35s as a credible minimum total order. Within the review, discussions are underway into continuing to balancing investment into the American-designed F-35 with funding into the UK-led next generation Tempest fighter jet programme. The financial balancing act also needs to take into account a scheme for a technological upgrade of the RAF’s Typhoon jets, which are set to be replaced by the Tempest jet from 2035.

No final decisions

No final decisions in the review had been taken and a government source told The Times: “With every review it is always the case people draw early and false conclusions from leaks. We advise against making assumptions based on partial information. The guiding principle of the [integrated review] is to ask ourselves what the threat is, and whether we have the capability to meet it.”

Britain is the only tier-one partner to the US, having invested $2 billion in the development of the F-35. About 15 per cent of the F-35 is made in the UK and there are global orders for 3,000 over the course of the programme.

The UK-led next generation fighter Tempest, is being developed as an aircraft which can be piloted by a human or operated remotely as an unstaffed platform which can control a swarm of unmanned combat drones. The project has attracted £2 billion of investment so far.

Tempest will attract a fraction of US investment

Tobias Ellwood, Conservative chairman of the Commons defence select committee, urged ministers to think carefully before slashing the number of total F-35 orders and warned: “We can’t keep eroding our spectrum of capability in this way.”

But The Times reported that Justin Bronk, a research fellow in combat air-power at the Royal United Services Institute, said that although a fleet of 70 F-35s would be “on the lower end of expectations”, it “makes sense”. He said the RAF could keep 60 in service, with ten held back to replace any aircraft lost to attrition or age-related damage. Bronk suggested that investment in Tempest may create British jobs, but was sceptical that the resulting jet would outperform the F-35.

“Even in an optimistic scenario, the UK and Italy with potentially other partners such as Sweden will be able to contribute a fraction of the investment in both development and acquisition of the US to a next-generation fighter programme,” he said.

“So it should be admitted up front that the overall capability is likely to be behind what the Americans are producing at a similar point, making the arguments for Tempest primarily sovereign industrial arguments rather than operational capability ones.”

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