The Defence Secretary hailed a “new phase” of the security arrangement between the UK, US and Australia.

The trio of allies have announced that there will be further collaboration in the areas of cyber and undersea warfare to build on the initial Aukus deal struck in 2021.

The so-called “second pillar” agreement announced on Saturday will see collaboration on artificial intelligence, electronic warfare, and quantum technology, while also agreeing to reduce barriers to sharing information and technology.

The first plank of the joint agreement, as first announced two years ago, will see Australia given support to achieve its first nuclear-powered submarines.

The vessels will not be nuclear-armed.

It will also provide the Royal Navy with replacements for its seven Astute submarines, potentially doubling the size of the fleet of its attack boats.

Aukus was agreed in recognition of China’s growing influence in the Indo-Pacific.

Defence Secretary Grant Shapps, who travelled to the US for the announcement about the second stage of the partnership, said: “Today Aukus enters a new phase.

“Together with our partners in the US and Australia we have strengthened our alliance to bring our armed forces closer than ever and ensure our nations are protected from new and advanced threats.

“As the world becomes more dangerous, Aukus only becomes more important in ensuring the UK and our allies maintain a strategic advantage.

“That is why we have today driven forward joint programmes on threat detection, quantum technology and autonomous systems.

“This progress will radically improve our shared ability to tackle emerging threats and demonstrates our commitment to making our militaries more lethal, more connected and more prepared.”

The allies also agreed what the Ministry of Defence (MoD) dubbed a “landmark radar initiative” to better detect, track and identify objects in deep space, with a site in Wales identified as the UK’s preferred location for the facility.

The Deep Space Advanced Radar Capability (Darc) programme will provide 24/7, all-weather capabilities that will increase the three nations’ ability to characterise objects deep in space up to 22,000 miles away from Earth, the MoD said.

Its creation is a recognition of the growing threat of space warfare.

Cawdor Barracks in Pembrokeshire, west Wales, has been identified as the UK’s preferred site for Darc.

The final decision for choosing a site is conditional on the results of the ongoing MoD-funded environmental impact assessment and subsequent town planning application.

Rishi Sunak
Prime Minister Rishi Sunak travelled to San Diego in March to finalise plans for the Aukus submarines deal (Stefan Rousseau/PA)

Cawdor Barracks is currently the home to a British Army Signals Regiment which is due to relocate from 2028.

Retention of the base for Darc would create employment during the construction phase and provide up to 100 longer-term jobs, Mr Shapps’ department said.

During their meeting in the States, Mr Shapps and his defence counterparts — US secretary of defence Lloyd Austin and Australian defence minister Richard Marles — agreed that “exceptional progress” had been made on delivering SSN-Aukus submarines to Sydney.

The MoD said progress included increased training opportunities for Australian sailors in the UK and US, and more planned visits of US and UK nuclear-powered submarines to Australia.

Prime Minister Rishi Sunak travelled to San Diego in March to finalise plans the plans for the subs.