Britain, Japan and Italy have signed an international treaty to establish a programme aimed at developing an advanced fighter jet, the defence ministers announced on Thursday.

This collaboration, emerging a year after merging London and Tokyo's fighter efforts, aims for the aircraft to take flight by 2035, pending parliamentary ratification. Led by Britain, the program's headquarters will host both government and industry entities. The jet promises a radar system significantly superior to current technology, with involvement from key players like BAE Systems, Leonardo, Rolls-Royce, and more from each nation.

The agreement, comes a year after the three countries established their first major defence industry collaboration by merging the separate next-generation fighter efforts of London and Tokyo.

The parliaments of each country must ratify the agreement, which aims to see the combat aircraft in flight by 2035. The joint development phase of the programme will begin in 2025.

Both the joint government headquarters of the Global Combat Air Program (GCAP) and its industry counterpart will be based in Britain. The government organisation's first chief executive will come from Japan, while the first leader of the business organisation will be from Italy, according to the announcement.

"No nation can do this alone to this level of expertise combined with our skills and our equipment, with our design and ability on production lines," British defence minister Grant Shapps said.

"As we face the most complex security environment since World War Two... securing aerial superiority continues to be a crucial challenge that we must achieve," Japan's defence minister, Minoru Kihara, added, flanked by Shapps and Italian Defence Minister Guido Crosetto in Tokyo.

Kihara did not say who would head the company, but said that he would ensure "the best person for the job" is selected.

The supersonic stealth jet will feature a radar that can provide 10,000 times more data than current systems, the British government has said.

Britain's BAE Systems, Italy's Leonardo, European missile maker MBDA and engine maker Rolls-Royce are involved in the project.

Japan's Mitsubishi Heavy Industries, Japanese avionics manufacturer Mitsubishi Electric Corp, and engine makers IHI Corp and Avio Aero are also involved.