A new generation of hunter-killer submarines will join the Royal Navy fleet following a deal between the UK, USA, and Australia – creating what is likely to be the largest, most advanced and most powerful attack submarine ever operated by the Senior Service.
The three-way arrangement will also see Australia acquire its first ever conventionally armed, nuclear-powered submarine through the Aukus – Australia-United Kingdom-United States – enhanced security partnership.
Called 'SSN-Aukus', the submarine will be built in the UK by BAE Systems and Rolls-Royce, and will eventually replace the Royal Navy's current Astute class submarines, potentially doubling its fleet.
SSN-Aukus will be the future attack submarine for both Australia and the United Kingdom.
Construction of the UK's first SSN-Aukus submarines will begin towards the end of this decade. A decision is yet to be made on how many new boats the Royal Navy will get but it will be based on the strategic situation at the time.
In appearance, the new submarines could resemble the Dreadnought Class, but smaller and will not be Britain's continuous-at-sea deterrent like the Dreadnought, but they will be larger than the Astute Class and designed for inter-operability, with a similar nuclear reactor, built by Rolls-Royce in the UK.
While the Astute Class can only fire Tomahawk missiles using torpedo tubes, the SSN-Aukus version will likely include payload modules for vertical-launch missiles and space for medium-sized, unmanned, underwater vehicles – all part of the inter-operability spec.
How will Aukus be rolled out and when?
The agreement, dubbed Aukus, will see the three countries work closely together and share technology.
According to a senior White House official, phase one is already under way with the US and UK submarines visiting ports in Australia, and will increase this year.
The senior White House official added: "Australian sailors will increasingly embed in US and UK submarine forces and nuclear power schools.
"This has already started. And, in the coming months, there'll be Australian workers in our shipyards. And starting this year, Australia will be building up its facilities and infrastructure to house Australia as well as US and UK submarines."
In 2022, the US accepted its first Royal Australian Navy personnel into nuclear propulsion training programmes, with additional personnel planned in the coming years.
Congress also approved Royal Australian submarine officers to train at the Naval Nuclear Power Training Command and eventually serve on operational US submarines and the UK also welcomed Australian submariners into the Royal Navy's nuclear courses. As early as 2027, there will be a rotational force of US and UK submarines in Australia – which will be named Submarine Rotational Forces West, to "bolster deterrence with more US and UK submarines forward in the Indo-Pacific".
Australian personnel will train with the Royal Navy and US Navy in the UK and the US. Phase two is set to start in the early 2030s, pending approval from the US Congress, the United States intends to sell Australia three Virginia class submarines, with the potential to sell up to two more if needed. SSN-Aukus will be built and deployed by both Australia and the UK. The UK is intending to deliver its first SSN-Aukus in the late 2030s and Australia intends to deliver its first SSN-Aukus and commissioned into the Royal Australian Navy in the early 2040s.
The Astute Class will remain the backbone of Britain's submarine fleet until the first SSN-Aukus submarines are delivered.
China condemns Aukus submarine plan as threat to peace in the Pacific
China has accused the UK, US and Australia of fuelling a new arms race after the agreement was announced.
China's Foreign Ministry said the pact arose from a "typical Cold War mentality", accusing the UK and US of violating the terms of the Nuclear Non-Proliferation Treaty (NPT) in transferring weapons-grade enriched uranium to a non-nuclear weapons power.
At a daily briefing in Beijing, spokesman Wenbin Wang said: "The latest joint statement issued by the US, UK, and Australia shows that the three countries have gone further down the wrong and dangerous path for their own geopolitical self-interest, completely ignoring the concerns of the international community."
It follows Monday's summit in San Diego, California, where Rishi Sunak, US president Joe Biden and Australian prime minister Anthony Albanese set out details of the latest stage of the Aukus partnership.
At a launch ceremony at a US naval base, Mr Sunak said the Aukus agreement was dedicated to keeping the oceans "free, open and prosperous" and "maintaining freedom, peace, and security now and for generations to come".
Downing Street responds to criticism from Beijing
Downing Street has defended its Aukus pact with Australia and the US for nuclear-powered submarines, after criticism from Beijing.
A No 10 spokesman said: "This is not about any one individual country, it's about investing in the capabilities we need to ensure UK security.
"We've set out the reason for the partnership and the aim of the partnership to deter aggression and enhance global security."
The agreement is expected to create thousands of jobs at British shipyards, with the UK's submarines mainly being built by BAE Systems at Barrow-in-Furness, Cumbria, and Rolls-Royce.