Dr Julian Lewis: Does the Prime Minister agree that one of the main reasons why NATO successfully deterred and contained the then Soviet Union, from 1949 to 1989, was that the rulers in the Kremlin were in no doubt at all that an attack on one NATO country would inevitably mean war with all the rest? For that reason, at the NATO summit will he bear in mind the fact that NATO membership – however hard-hearted this may seem – must never be offered to a country unless we are prepared to go to war to defend that country?

[The Prime Minister: My hon. Friend speaks very good sense about this. Article 5 obligations are deadly serious and we would have to meet them if a NATO member was invaded by another country, so the point he makes is a good one.]