Sir, – President Putin’s implicit threat to use nuclear weapons first should any country try to stop his invasion brings into sharp focus the importance of our nuclear deterrent. In the past we have always emphasised that the UK has a ‘minimum’ credible deterrent and been ambiguous about the circumstances of when we would use it. It is time to make it clear to Putin, alongside our NATO allies, that if he uses nuclear weapons the response, even from just one UK ballistic missile submarine, would be instant and devastating. It is not clear whether Putin listens to his advisors, but this blunt me…
