LAURENCE REES: How crucial is it for Britain that Winston Churchill becomes Prime Minister in May 1940?

ANDREW ROBERTS: I think it’s very important that Churchill becomes Prime Minister in 1940, because the alternative would have been Lord Halifax who didn’t really understand military matters at all. He wasn’t interested in them and he was somebody who would have left all the fighting up to the generals and wouldn’t have imposed himself in any way. He also wasn’t, of course, the charismatic figure that Winston Churchill was, and therefore would have found it much more difficult to have  infused the nation for the fight when obviously, after Dunkirk and the Battle of Britain, he desperately needed morale to be high, and Halifax couldn’t have done that. And so really Winston Churchill was the best choice because of who he wasn’t, and at the same time he was somebody who really, because of the 10 years of warning about the Nazis, had a moral power that was completely lacking in pretty much any other major frontline British statesman of the day.

LAURENCE REES: But the previous 6 months of him running the admiralty had been pretty much a disaster?

ANDREW ROBERTS: He made lots of mistakes and he was going to continue to make mistakes and he was going to make a lot of suggestions that had to be knocked down by the chiefs of staff, but the fact was that he never once overruled the chiefs of staff on a major strategy issue; he’d leant his lesson from Gallipoli and from disasters that overcame him a quarter of a century earlier. And therefore when he was Prime Minister and Minister of Defence, a key job that he took on at the same time, he was able to hold himself back really and it was very important for the chiefs of staff to keep a lid on it. But, nonetheless, if you’d had Halifax who had no ideas of his own at all, strategically he wouldn’t have been able to have put anything into the mix.

LAURENCE REES: And so of course Churchill takes over in May 1940. And he presides over a series of meetings at which there is this suggestion by Halifax that Mussolini could be used in order to try and see what peace terms Hitler might want. How crucial is it for the fate of Britain that Churchill doesn’t progress with that?

ANDREW ROBERTS: I think in those meetings Halifax said that he wouldn’t make peace with Hitler if our Central Sovereignty or the Royal Navy was put at risk, and Hitler would have been perfectly happy to have made terms which didn’t either entail the Royal Navy or our Sovereignty, so it would have happened, I think, had he become Prime Minister. Lord Halifax could well have made peace. And I think that would have been utterly disastrous for Britain in the long term. It would have meant that Hitler would have had a completely free hand.