The new US-UK-Australia alliance announced by Joe Biden, Boris Johnson and Scott Morrison overnight – under the acronym AUKUS – is a major development in the strategy of all three countries – more than may appear at first sight. It is full of hidden nuances and subtleties, not yet made public, but is a huge boost for the Royal Navy, the submarine service, and British submarine technology. The most obvious novelty is that Australia is to build nuclear-powered attack submarines for the first time. They will be SSN hunter-killer vessels, for intelligence gathering as well as deterrence across the wider Pacific region. The boats are likely to be based on the current Virginia class now entering service with the US Navy or the Royal Navy’s Astute class – and most likely to be an amalgam and update on both.