The AUKUS strategic partnership will enable the UK to deliver increased submarine presence across the Mediterranean and North Atlantic regions, a senior UK government official has said.

Signed in September 2021, the Australia/UK/US agreement was designed to produce nuclear-powered attack submarines (SSNs) for Australia and the UK (through the SSN-AUKUS programme), plus a host of other leading-edge naval technologies for all three partners. Its strategic-level aim is to generate enhanced maritime defence capability across both the Euro-Atlantic and Indo-Pacific theatres. Here, the UK’s and Australia’s broad areas of strategic interest around the world are linked together by their mutual relationships – plus the AUKUS trilateral partnership – with the US.

Opening the annual Undersea Defence Technology (UDT) conference, being held in London in 2026, Sir Stephen Lovegrove – the UK Prime Minister’s Special Representative on AUKUS – said “Having more SSNs, swift and undetectable in the water, is an unequivocal good for our society, our security, and those of our allies.”

“This audience knows the primacy of the SSN as a warfighting platform and an instrument of deterrence better than any other,” he said. “No other conventional capability can match its potency, or its ability to confuse and complicate our adversaries’ decision-making calculus.”

“With the US capability inserts making SSN-AUKUS fully interoperable with the [US Navy’s] formidable Virginia-class [SSN] fleet, it will mean that AUKUS partners are collectively able to field a higher number of more capable attack submarines, as part of a more flexible network across the globe, at any one time,” Lovegrove stated.

However, while noting the UK’s contribution to Indo-Pacific security, Lovegrove stressed “Let there be no mistake that, [given] where the bulk of the UK’s boats will be deploying, AUKUS means we will have more boats – and more capable boats – in our primary theatres, the Atlantic and the Mediterranean.”

In his discussion of the deepening geopolitical volatility and contested ocean spaces that characterise international security today, Lovegrove noted a number of security challenges that illustrate starkly the threat to security in and around the Mediterranean and North Atlantic regions. These included the shipping crisis in the Strait of Hormuz, recent Russian submarine deployments against North Atlantic critical undersea infrastructure (CUI), and Russia’s war in Ukraine threatening trade routes including grain supplies through the Black Sea.

“All of these are powerfully – and powerfully painful – real-world reminders of the consequences of disordered navigation and the vulnerability of our CUI,” Lovegrove continued. “Unfortunately, it is clear that disruptive actors do have the capability, and have increasingly shown they have the will and the means, to exploit these vulnerabilities and to contest the maritime domain.”

To combat this challenge, the AUKUS programme will deliver sophisticated capabilities at the speed of relevance, and will strengthen collective deterrence and security across both the Indo-Pacific and Euro-Atlantic theatres, Lovegrove added.

For the UK and its allies, he underlined, “The oceans have become the primary space for signalling strength, enhancing deterrence, and countering coercion.” So, against this backdrop, Lovegrove said, “AUKUS has taken on more relevance and has a stronger strategic logic than it ever had before.”

He noted that, in 2025, all three partners had reviewed the AUKUS accord, and had renewed their respective commitment. “There was considerable, and public, speculation about the future direction of AUKUS last year. I want to be clear, now: that has been unequivocally put to bed …. That chapter is now firmly shut,” Lovegrove said. “Our leaders and defence ministers made clear in Washington in November [2025] that we were ‘all in’ on AUKUS.”

From the UK’s perspective, Lovegrove explained, this strategic re-commitment has been reflected in the confirmation of a further GBP 6 billion investment across BAE Systems’ Barrow submarine-building and Rolls-Royce’s Derby nuclear reactor facilities. This investment is transforming those facilities and helping underpin both the delivery drumbeat of 18 months per submarine on the UK’s new SSN-AUKUS boats and the commitment to grow the UK’s SSN flotilla size from seven to perhaps up to 12 platforms, he added.

“That drumbeat and that investment … is fundamental to our efforts in ensuring that the Royal Navy and the Royal Australian Navy get their boats on schedule,” Lovegrove said.

The first SSN-AUKUS submarine is scheduled for delivery from Barrow’s production line in the late 2030s. Boats built in Australia are scheduled to start arriving in the early 2040s.