HH
Building SSN's is another example of our Defence "thinking". We need subs, the USN needs them and has nukes as do the Russians so we must have nukes too. Export potential is zero so it's all about retaining a strategic nuclear submarine building ability at Barrow as much as a defence capability.
Problem was that after Upholder and the Trident build, we had no follow on programme and let many skilled sub workers go. Barrow tried to diversify building Bulwark and Albion, a story in itself but to cut to the chase, when we went for Astute we pretty much had to start again but needed help from the US to finally produce a boat well in excess of what was needed after the end of the Cold War. As it's all we can build, we have ordered another to keep Barrow in work until the Trident replacement is ready to start and this can't be delayed to match the potential expiry date of the Trident boats.