HMS Anson (S123): The Newest Hunter-Killer, First to Refit in Australia

Built at Barrow

HMS Anson was built by BAE Systems at Barrow-in-Furness, launched on 20 April 2021 and commissioned on 31 August 2022, the fifth Astute-class nuclear-powered fleet submarine and the eighth Royal Navy vessel to carry the name, honouring Admiral George Anson, 1st Baron Anson, the celebrated eighteenth-century circumnavigator and naval reformer.

The Man She Is Named After

Celebrated is one word for it. Anson's voyage round the world is among the most successful and by some distance the most appalling in the history of the Royal Navy, and it is worth knowing about because it bears directly on the submarine that now carries his name.

He sailed from Portsmouth on 18 September 1740 with six ships and something like nineteen hundred men, under orders to round Cape Horn and attack Spanish possessions in the Pacific. Cape Horn very nearly finished him. The squadron was scattered and battered in the gales, one ship was wrecked, others turned back or were scuttled, and by the time he crossed the Pacific he had a single vessel left, his flagship Centurion.

The killer was not the Spanish and it was not the weather. It was scurvy. More than thirteen hundred of those nineteen hundred men died, the great majority of them from a vitamin deficiency nobody yet understood, which rots the gums, reopens old wounds and kills men who are otherwise perfectly healthy after a few months without fresh food. Anson watched most of his command die of it and could do nothing whatever.

On 20 June 1743, off Cape Espiritu Santo in the Philippines, the survivors caught what they had come for: the annual Manila galleon, the Nuestra Señora de Covadonga, carrying the year's silver. The treasure was worth roughly four hundred thousand pounds, an enormous sum, and it was paraded through London on wagons when Centurion got home on 15 June 1744. Anson was made a rear admiral and a baron and became one of the richest men in England.

What he did with the rest of his life matters more. He became First Lord of the Admiralty in 1751 and set about reforming a navy he had seen kill its own people through neglect. Among the things built in that period was the naval hospital at Haslar in Gosport, and its first chief physician was James Lind, the man who established that citrus fruit cured scurvy. The admiral whose crews had died of the disease presided over the institution where it was beaten, and Haslar stands a few hundred yards from where the Royal Navy's submarine service later made its home.

A Formidable Package of Sensors and Weapons

Anson carries six 21-inch torpedo tubes with capacity for up to 38 weapons, including Tomahawk Block IV cruise missiles with a range of a thousand miles and Spearfish heavyweight torpedoes, alongside Thales Sonar 2076 and two CM010 optronic masts in place of a traditional periscope.

Her nuclear reactor needs no refuelling across a 25-year service life, and she can purify her own water and air, giving her extended underwater endurance limited more by her crew's supplies than by the boat herself, with provisions for 98 officers and ratings and food for three months at sea.

That last clause is the point at which the two Ansons meet, and it is a genuinely neat piece of naval continuity. A modern nuclear submarine has effectively solved every problem that destroyed the 1740 expedition except one. She does not need wind, so Cape Horn holds no terrors. Her reactor runs for twenty-five years without refuelling, so fuel is not a limit. She distils her own fresh water out of the sea and makes her own oxygen by splitting it, so air and water are not limits either.

What is left is the crew, and specifically what the crew can eat. The endurance of the most sophisticated warship Britain has ever built is set by how much food will fit inside her, which is about three months. Two hundred and eighty years apart, the two vessels named Anson are bounded by exactly the same thing: not the ship, but whether the people in her can be kept going. HMS Warspite holds the Royal Navy record for how far that can be pushed.

Sea Trials and a Global Deployment

Anson completed her sea trials on 21 May 2024, and by February 2025 was docking in Gibraltar to load weapons ahead of further operations.

In early 2026 she deployed east of Suez to Australia, arriving at HMAS Stirling in Western Australia that February for the first maintenance period ever carried out on a UK nuclear submarine on Australian soil, a milestone ahead of the Submarine Rotational Force-West due to begin operating from the same base in 2027, before being positioned in the Arabian Sea in March 2026 during a period of regional tension.

The Australian part of that deserves its context, because it is a policy milestone rather than a routine port visit. Under the AUKUS agreement, Britain and the United States are to establish Submarine Rotational Force-West at HMAS Stirling in Western Australia from 2027, with British and American nuclear submarines operating from the base while Australia builds towards a submarine force of her own. Nothing of that kind works unless the host country can actually maintain the boats.

That is what the February 2026 visit was for. Carrying out a maintenance period on a British nuclear submarine on Australian soil, for the first time ever, is the practical proof that the arrangement can function, and it had to be demonstrated before the rotational force begins rather than afterwards. It is the least glamorous milestone in the whole programme and probably the most important one.

Beyond that, what Anson was doing on this deployment is not public and is not guessed at here. Submarine movements are announced when a government wants them announced, which is usually to make a point, and the rest stays where it belongs.

She returned to Gibraltar that May en route back to UK home waters, a particularly global itinerary for one of the Navy's newest and most capable attack submarines.

She is the fifth of seven Astutes, following HMS Astute and HMS Artful, and the class has been a long time coming: the programme ran years late and well over budget, which is close to standard for nuclear submarine construction anywhere in the world. The boats themselves, once delivered, are generally reckoned among the most capable conventionally armed submarines afloat.

A first deployment that takes in Gibraltar, the Indian Ocean, Western Australia and the Arabian Sea inside about six months is a substantial way to begin a career. Anson has roughly a quarter of a century of it in front of her, and on current form her namesake would have approved of the reach and been quietly astonished that everybody came home.

This is a live article which will be updated when more information is available.