Sixth Royal Navy Astute-class SSN commissioned at Barrow-in-Furness

HMS Agamemnon, the sixth of seven Astute-class nuclear-powered attack submarines (SSNs) ordered for the UK Royal Navy, was commissioned at BAE Systems’ site at Barrow-in-Furness on 22 September 2025 in a ceremony attended by His Majesty King Charles III.

Although now officially commissioned, HMS Agamemnon will now complete a test and commissioning programme before leaving Barrow for sea trials, meaning that it will probably be another 18 months or so before the boat is properly operational. The Royal Navy normally holds its commissioning ceremonies after vessels have completed contractor’s sea trials and been accepted from the builders.

The website navylookout.com noted that Agamemnon holds the record for the longest construction time of any nuclear submarine ever built for the RN, with more than 12 years having passed since the boat was laid down. This is partly due to the Covid-19 pandemic disrupting production and a temporary diversion of resources to begin the programme to build the Royal Navy’s future Dreadnaught class of four nuclear-powered ballistic missile submarines (SSBNs), although navylookout.com also cited “the toxic legacy left by the poor foundations of the wider Astute programme”.

Armed with Spearfish heavyweight torpedoes and Tomahawk cruise missiles, the Astute-class SSNs are tasked with protecting the Royal Navy’s SSBNs and carrier strike groups, as well as UK and allied critical underwater infrastructure.

Prior to the commissioning of Agamemnon at Barrow, UK Defence Secretary John Healey took part in a ceremony that cut the first steel for construction of the last Dreadnought-class SSBN, which will become HMS King George VI.

The first SSBN of the class, Dreadnaught, which was laid down on 20 March 2025, is due to enter service in the early 2030s.