Boris Johnson was joined by US President Joe Biden and the Australian Prime Minister to announce a “landmark” new defence and security partnership between the three countries.
The AUSUK alliance was announced in a late-night joint press conference hosted by the three leaders on Wednesday.
The UK Government said it would enhance the development of joint capabilities and technology sharing, ensuring people are “kept safe from harm and reinforcing our shared goals”.
The first focus of the initiative will be on collaboration on the development of nuclear-powered submarines for the Royal Australian Navy.
“This capability will promote stability in the Indo-Pacific and will be deployed in support of our shared values and interests,” the leaders said.
Prime Minister Boris Johnson said: “The UK, Australia and US are natural allies – while we may be separated geographically, our interests and values are shared. The AUKUS alliance will bring us closer than ever, creating a new defence partnership and driving jobs and prosperity.
“This partnership will become increasingly vital for defending our interests in the Indo-Pacific region and, by extension, protecting our people back at home.”
A joint statement from the three leaders said the endeavour would “help sustain peace and stability in the Indo-Pacific region”.
It added that the pact would also focus on cyber capabilities, “artificial intelligence and additional undersea capabilities”.
In a televised address, Boris Johnson said the agreement would bring the “natural allies” closer together.
Mr Johnson added: “Perhaps most significantly, the UK, Australia and the US will be joined even more closely together, reflecting the measure of trust between us, the depth of our friendship, and the enduring strength of our shared values of freedom and democracy.
“Now the UK will embark on this project alongside our allies, making the world safer and generating jobs across the United Kingdom.”