Britain has entered into a security pact with the US and Australia to counter China that will involve building a nuclear powered submarine fleet and wide-ranging projects on cyber warfare, artificial intelligence and quantum computing.

Senior British officials insist the new alliance is not aimed at any one country, but it comes in the face of increasingly aggressive posturing from China and has the stated aim of protecting the “rules-based international order” that Beijing has been accused repeatedly of flouting.

The first programme of the AUKUS alliance will be the construction of a fleet of nuclear-powered submarines for the Australian navy, with American and British companies taking part in the manufacturing process.

The agreement, described as one of the most significant of its kind for decades, was announced in Washington, London and Canberra by US president Joe Biden and prime ministers Boris Johnson and Scott Morrison on Wednesday.

“The UK, Australia and US are natural allies – while we may be separated geographically, our interests and values are shared,” Mr Johnson said.

“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.”

The naval plan will upgrade Australia’s electric and diesel-powered submarine fleet to nuclear-powered, while, alliance members stress, still complying with Canberra’s adherence to nuclear non-proliferation treaties.

Australia is committed to the “highest standards for safeguards, transparency, verification, and accountancy measures to ensure the non-proliferation, safety, and security of nuclear material and technology,” the announcement said.

The initiative for the building of the fleet came from the Australian government in February. The initial phase of the programme will take 18 months and a number of British firms are expected to be involved in the project.

Only China and India currently operate nuclear-powered submarines in the Indo-Pacific region. India is regarded as an Australian ally and the two countries have regularly carried out military and naval drills together.

Relations between Australia and China have been increasingly fraught after Canberra called for an independent investigation into the origins of the coronavirus pandemic and criticised Beijing’s crackdown in Hong Kong and its treatment of the Uyghurs in Xinjiang, as well as its aggressive stance on territorial waters.

China has retaliated with punitive restrictions on Australian imports. Hacking groups linked to Beijing have been accused of carrying out cyber attacks on a number of targets in Australia, including the country’s infrastructure, government services and educational establishments.

There have been encounters between the navies of the two countries on a number of occasions, including last year when five Australian warships were on their way to an exercise with the US near Hawaii.

A number of countries have carried out right-of-navigation voyages in the South China Sea, including, recently, a British naval strike force led by the aircraft carrier Queen Elizabeth. The Chinese have frequently accused the countries involved of being provocative, and have warned of consequences if they were to venture into waters it claims as its own.

Announcing the “landmark defence and security partnership … which will protect and defend our shared interests in the Indo-Pacific,” the alliance said: “The region is at the centre of intensifying geopolitical competition with multiple potential flashpoints: from unresolved territorial disputes; to nuclear proliferation and miscalculation”, continuing: “It is on the frontline of new security challenges, including in cyberspace.”

Downing Street stressed the potential financial benefits to Britain, saying the UK “has built and operated world-class nuclear powered submarines for over 60 years.

“We will therefore bring deep expertise and experience to the project through, for example, the work carried out by Rolls-Royce near Derby and BAE Systems in Barrow,” it said.

“The design and build process will create hundreds of highly skilled scientific and engineering roles across the UK, and drive investment in some of our most high-tech sectors.”