The newest Royal Navy conventionally armed nuclear-powered submarine, HMS Agamemnon and nicknamed ‘Awesome Aggie’, will now begin sea trials – a period of testing ahead of joining active service with the Royal Navy.
The Astute-class are the largest, most advanced and most powerful attack submarines ever operated by the Royal Navy. Weighing 7,400 tonnes and at 97 metres long, they are just short of the length of two Olympic swimming pools. Powered by a Rolls-Royce Submarines nuclear reactor, produced in Derby in the Midlands, the submarine will not need to refuel for the duration of her service life.
The submarine’s high-tech capabilities include stealthy precision strike, anti-submarine warfare, and intelligence gathering. HMS Agamemnon will be armed with heavyweight Spearfish torpedoes and Tomahawk IV land attack missiles, able to strike targets at a range of more than 1,000 miles.
Alongside their role supporting the continuous at sea deterrent, Astute-class submarines are also involved in protecting maritime task groups and providing support to UK, NATO and coalition operations.
Prime Minister Andy Burnham said:
Having seen first-hand the dedication and pride of the workforce in Barrow, and that of the thousands of people who work across our submarine supply chain in the United Kingdom, I know how much this milestone will mean to each and every one of them.
As one of the most advanced submarines ever built, HMS Agamemnon will play a major role in further boosting our security here at home and across NATO.
Defence Secretary, Wes Streeting MP said:
Deterrence is the bedrock of our national security. Another formidable attack submarine going to sea strengthens that deterrence and demonstrates how we are stepping up to meet the threats of a more dangerous world.
I’ve been on board HMS Agamemnon and met her submariners and the skilled workers who delivered this incredible feat of engineering. It’s a powerful reminder of how strengthening our defence creates good jobs, opens up opportunity, and reindustrialises our country.
HMS Agamemnon’s departure from Barrow-in-Furness is the result of years of work by a highly skilled workforce. This includes the engineers, technicians and specialists at BAE Systems and the Defence Nuclear Enterprise (DNE), together with the ship’s company who will take her into service. Their combined expertise reflects the depth of skill sustained in Barrow and across the UK’s submarine enterprise.
Maddy McTernan, Chief of Defence Nuclear, said:
HMS Agamemnon’s departure is a significant moment for the UK’s Defence Nuclear Enterprise and is a clear demonstration of the engineering and industrial excellence of the Barrow workforce and across the wider UK supply chain.
Submarine production will continue to boost British industry for decades to come backed by the commitments announced in the recent Defence Investment Plan.
Royal Navy First Sea Lord, General Sir Gwyn Jenkins, said:
In an increasingly dangerous world, sea power remains fundamental to keeping our country and people safe. Our submarine fleet is essential to that effort, which is why I am delighted that HMS Agamemnon, the sixth of our Astute-class submarines, has now begun sea trials and will soon arrive at HMNB Clyde to join the fleet.
She embodies the best of British engineering and the professionalism of our submariners and will be one of the most advanced submarines ever operated by the Royal Navy.
As we continue to strengthen our warfighting readiness, HMS Agamemnon will play a central role in keeping the United Kingdom safe, contributing to NATO’s collective defence and ensuring we are ready to lead, fight and win.
Building on commitments to continuous submarine production made in the 2025 Strategic Defence Review, and reinforced in the Defence Investment Plan (DIP), the completion of HMS Agamemnon demonstrates the strength and reliability of British industry and its world-leading nuclear technology.
The DIP is backed by £298 billion over the next four years, including £47 billion for investment in our submarine build programmes, which also covers maintenance and infrastructure. Part of that spend will enable the UK to produce a submarine every 18 months in support of the SSN-AUKUS programme.
Recognising Barrow’s role as a strategic national asset, DNE spending is fuelling substantial growth and expansion in the town. The economic certainty from the government’s commitment to the submarine building programme underpins the 10-year Plan for Barrow, backed by the £200 million Barrow Transformation Fund. More than 14,000 roles in Barrow-in-Furness are supported by defence nuclear work, with 1,800 additional roles created in Barrow under this government.
HMS Agamemnon has been delivered as part of a national endeavour by the MOD’s DNE, the partnership organisations that operate, maintain, renew and sustain the UK’s nuclear deterrent. The DNE supports over 47,000 jobs across the UK, including thousands of highly-skilled roles involved in submarine production.
Marking entry into the Royal Navy, HMS Agamemnon was formally commissioned by His Majesty the King in a ceremony on 22 September 2025. She is the sixth Navy vessel to bear the name.
The seventh and final submarine in the class, Achilles, is at an advanced stage of construction in Barrow. The Astute Class will be succeeded by up to 12 new SSN-AUKUS nuclear-powered attack submarines from the late 2030s, with steel due to be cut for the first-in-class in Barrow next year, continuing the town’s role at the heart of AUKUS delivery.