Dr Julian Lewis: Much as no one wishes to see the Cold War return, do not recent events between Russia and Ukraine indicate that this is not some flight of fancy, but that it really could happen, and does that not mean that we must be extremely careful never to let down our nuclear or conventional defence guard?

[The Secretary of State for Defence (Mr Philip Hammond): What those events do show is that we have been right throughout in maintaining the need to continue with a strategic nuclear deterrent as the ultimate guarantor of Britain’s sovereignty and freedom of action. The world is a very uncertain place, while the time horizons for the provision of military equipment are very long, and we are looking forward 40 or 50 years in the planning. The events of the past months and years show that it would be a very brave man indeed who said that there would be no threat to our sovereignty and independence over that time horizon.]