[6][7] This would be developed by an industrial consortium known as Team Tempest consisting of BAE, Rolls Royce, Leonardo, and MBDA working in conjunction with the Ministry of Defence and the Royal Air Force's Rapid Capabilities Office.

[8] On 19 July 2019, Sweden signed a Memorandum of understanding (MoU) with the UK to work together in developing the wider FCAS needed for the future of aerial operations.

[14] Japan, an island nation, has a disproportionately vast air defence identification zone given the size of its land territory, and it was expected that the country would have to protect it with a smaller fleet of fighters compared to those of its growing neighbours with much larger populations.

Following the USA's decision not to allow the export of the F-22 Raptor to any other country in 2007, Japan began looking for a domestic solution to field a new fighter aircraft to replace its Mitsubishi F-2 fleet.

From the mid-2000s Japan began funding various research programmes involved in fighter design culminating in the Mitsubishi X-2 Shinshin experimental aircraft which took flight on 22 April 2016.

In 2018, after more than a decade since America's refusal to export the F-22, Lockheed Martin proposed a potential Japan-America collaboration project to develop the F-2 successor based on the F-22 and F-35, but this was rejected by Japan.

[25] On 15 February 2022, a further agreement was reached between both nations to jointly develop sensor capabilities for their respective fighters known as the 'Japan and Great Britain Universal Advanced RF (radio-frequency) system' or 'JAGUAR'.

[31] In late December 2022, two weeks after GCAP was announced, Japan and Sweden signed an ‘Agreement on the Transfer of Defence Equipment and Technology' that would explore deeper bilateral ties between both nations.

[34] While the UK and Italy were reportedly open to the concept, Japan was firmly opposed, seeing Saudi membership as a complication to both further domestic efforts in allowing Japanese defence exports to foreign nations and to the overall timeline for the programme in successfully producing an in-service aircraft by 2035.

[34][35] There were also concerns from defence sources that the security of sensitive technology might be complicated by Saudi membership as well as the questionable technical contribution that the Kingdom could feasibly provide to the programme.

However, Shepard News reported that this leak might potentially be a German negotiating tactic to pressure France and Spain to concede to Germany's demands for the programme.

Whilst such a decision does not rule-out future Swedish participation in GCAP, delaying membership in the programme would risk losing industrial influence over design requirements.

[42] In late July 2024, Leonardo chief executive Roberto Cingolani said he would be “personally very open” to Saudi Arabia joining if Britain decides to reduce its commitment, “especially if there were some reallocation of resources” after the UK’s new Labour government completes its defence spending review.

The talks are expected to conclude by the end of the year, with Italian Foreign Minister Antonio Tajani confirming that Saudi Arabia is likely to join the programme.

This treaty would see both the collaborative governmental headquarters and industrial hub for the effort be based in the UK, confirming earlier reports,[36] with Japan providing the first CEO and Italy the first leader of the business entity.

This would culminate in the formation of the GCAP international Government Organisation (GIGO) which would be responsible for managing the development of the fighter once the nations' respective political bodies gave their approval.

[47][48] The Defense of Japan 2024 white paper outlined that the GIGO would first see technical officials dispatched as technology experts and a sophisticated and secure working environment established to ensure a smooth and reliable development process for the aircraft.

Therefore, to ensure this remains compatible with requirements of the UK and Italy, and that the aircraft could be exported to further reduce costs (economy of scale), a mechanism had to be created to enable such transfers.

[56] On 15 January 2025, the UK Ministry of Defence (MoD) announced that the GIGO would be headquartered in Reading and led by its first Chief Executive Mr Oka Masami from Japan.

[57] On 13 December 2024, the three national industrial partners for the GCAP announced the formation of a business joint venture that will be accountable for the design, development, and delivery of the aircraft by the mid-2030s and throughout its expected service life beyond 2070.

[58][59] In December 2024, Leonardo stated that it had already signed GCAP-related R&D contracts worth €100 million with subcontractors in Italy, whilst the Italian MoD had earmarked €8.8 billion to the programme.

[62] On July 14 2023, the RAF awarded Leonardo UK and 2Excel a £115 million contract to enable the Excalibur Flight Test Aircraft (FTA) to transition into second phase development.

Dimensions for the technology demonstrator have not been revealed but, due to the size of its engine ducts publicly showcased by BAE Systems, it is estimated the aircraft is likely a third larger than a Eurofighter Typhoon.

[70][71][72] Whilst there has yet to be official dimensional characteristics released for the fighter, Janes' Gareth Jennings in attendance of the unveiling talking of the scale model drew comparison to the 19 metre wingspan of the F-111 Aardvark.

[75] In July 2024, during the Farnborough Airshow, Airbus had reportedly suggested that its Wingman Unmanned Adjunct (WUA) could be developed for GCAP with help from the programme's industrial partners.