>>Half a century later and we no longer have the capability to build a new reactor
We do, many of those knowledgeable in doing so are still around and living in the UK. The only thing stopping them from being used, is that they are of Iranian nationality. In the 60's and 70's when Iranian nuclear physics graduates were being churned out of universities, western governments were snapping them up. Nowdays Iranian = terrorists in the same governments eyes, so they are overlooked.