Japan is growing increasingly doubtful about the UK’s commitment to their joint fighter development programme with Italy, with crucial development work stalled by British budgetary foot-dragging.
The Global Combat Air Programme (GCAP), which aims to put next-generation fighters in the skies by 2035, is a landmark effort by Japan, the UK and Italy to challenge US dominance in military technology.
But a series of delays to the UK’s defence investment plan is preventing the signing of a vital contract for design and development work with Edgewing, the commercial joint venture between the three nations’ leading defence contractors.
“Frankly speaking, it’s a terrible situation,” said one person involved in GCAP, referring to the hold-up of project work caused by the UK.
A second person involved acknowledged there was a sense of “growing frustration” on the part of Japan.
In addition to funding questions, two people familiar with the matter also suggested the two capitals had different priorities for the programme.
Tokyo’s main aim is to produce a new fighter by the mid-2030s, whereas London and Rome are more interested in GCAP producing a cutting-edge “system of systems” — a jet that operates in concert with a swarm of drones — over a less rigid timetable, one of the people said.
One of them added that this could leave the UK “tempted” to try to slow the timetable to make it more affordable in the short term.
The friction between the governments comes at a time when anxieties are rising about global security because of the war in the Middle East and an unpredictable US under the Trump administration that has urged its Nato allies to do more to defend themselves.
GCAP was intended to create a successor to the current generation of jets flown by the three nations, helping to reduce reliance on more advanced F-35 fighters supplied by the US, which are a mainstay for Nato air forces.
The UK had initially planned to publish the 10-year defence investment plan in autumn 2025, but this has been repeatedly postponed because of fiscal constraints with a funding gap identified of up to £28bn over a decade, according to officials.
At the start of this year, Italy estimated that its share of the design and development phase would cost €18.6bn, triple its previous forecast. Last month, Rome approved a budget that included an €8.8bn tranche of funding for the programme.
Japan’s deepening worries over the delays to the UK’s defence spending plans and whether GCAP’s funding requirements will be ringfenced have been expressed at ministerial levels, the people said.
UK Prime Minister Sir Keir Starmer tried to reassure Japanese counterpart Sanae Takaichi of Britain’s commitment during his visit this year, but in the absence of any funding his reassurances did not hold much sway, said two people familiar with the visit.
The programme’s industry partners had expected the international contract to be signed last September. The contract would have released the next tranche of funding — expected to be in the billions of pounds — to the Edgewing consortium. The signing, however, was repeatedly pushed back amid delays to the publication of the UK’s defence investment plan.
The main companies involved — BAE Systems, Italy’s Leonardo and Japan’s Mitsubishi Heavy Industries — have continued engineering and design work under existing national funding streams, but fear the UK money will run out in the coming weeks, according to two people familiar with the programme.
Tokyo has shifted its stance to become more open to signing deals with potential customers for the fighter jet to reduce the funding requirements on the UK, with Canada a leading potential customer, according to two of the people.
Japanese officials stressed that Tokyo is reluctant to allow the entry of any new design and development partner, however, given the complexities. Japan resisted a push last year by the UK and Italy to get Saudi Arabia involved in the development. Saudi Arabia was still in talks to join in some form, according to two people familiar with the situation.
UK defence secretary John Healey told MPs this year he was “determined that the momentum of the [GCAP] programme is maintained”. On Monday he told parliament the government was “working flat out to settle the defence investment plan”, but gave no sign it was due to be published imminently.
A UK Ministry of Defence spokesperson said: “The depth of collaboration between all three nations is clear — in the last year alone we’ve seen the trilateral GCAP headquarters open in Reading and the launch of the joint venture made up of industry organisations from all three nations to deliver the programme.
“Our immediate priority is working with all parties on signing the first major international contract for GCAP as soon as possible.”
Japan’s Ministry of Defence said Edgewing contract negotiations were in the final stages and “we do not believe this will lead to delays in the programme”. It added that “if there are countries expressing their interest, we will, together with the UK and Italy, take their interest and perspectives into account and respond in a way that helps improve the programme”.
An Edgewing spokesperson said GCAP is “proceeding on schedule, with engineering work . . . moving briskly forward”. The “GCAP Agency and Edgewing are continuing to ramp up and operate in line with our planning,” they added.