HMS Anson – dubbed the "most advanced submarine ever built by BAE Systems" – has been officially commissioned into the Royal Navy during a ceremony in Barrow-in-Furness, Cumbria.
The nuclear-powered submarine is 97m long with a displacement of 7,800 tonnes and is the fifth of seven in the Astute class.
Astute submarines are recognised as the most technologically advanced attack submarines ever operated by the Royal Navy.
The submarine is armed with a combination of Spearfish torpedoes and Tomahawk Block V cruise missiles, allowing her to take out targets at long range, and she can circumnavigate the globe submerged, producing oxygen and drinking water for the crew.
Wednesday's traditional naval ceremony was attended by a number of dignitaries, including the submarine's Lady Sponsor, Julie Weale, the Australian Deputy Prime Minister Richard Marles and UK Defence Secretary Ben Wallace.
Mr Wallace highlighted the "significant milestone" that this commission is in the UK and for Australia's preparation to "confront growing threats to the liberal democratic order, especially in the Indo Pacific".
Defence Secretary Ben Wallace explains why HMS Anson's commissioning is so significant.
"Not only have we progressed our defence planning," Mr Wallace said, "but Minister Marles participated in the commissioning of our latest attack submarine, on which Royal Australian Navy submariners will be embarked as we develop our shared capabilities in the years ahead.
"Built in a UK shipyard, HMS Anson demonstrates the very best of British industry, sustaining our world-leading sub-surface capabilities and underlining the UK's readiness to contribute them to shared security, especially with our closest allies Australia and the United States under the AUKUS initiative."
"Among the finest engineering accomplishments in the world"
The Dreadnought class submarines, which will replace the Royal Navy's Vanguard-class, carrying the UK's independent nuclear deterrent, are also being designed and built in Barrow.
Manufacturing work is well under way on the first two of four Dreadnought submarines, with the first of class due to enter service in the early 2030s.
The third programme being undertaken by BAE Systems is for the Royal Navy's next generation of submarines which will eventually replace the Astute class, referred to as SSN-Replacement (SSNR).
Early design and concept work formally began following an £85m contract award by the Ministry of Defence in 2021.
Watch: £2 billion-plus to boost Dreadnought nuclear submarine programme.
BAE Systems chief executive Charles Woodburn said: "The Astute class submarines are among the finest engineering accomplishments in the world.
"As the custodian of the UK's submarine design and build capability, we're incredibly proud of the role we play in the delivery of this strategic national endeavour."
BAE Systems has delivered the first four submarines in the Astute class which are currently in service with the Royal Navy. The sixth and seventh boats are at an advanced stage of construction at Barrow.