Here's a guest post from my colleague Hannah Brenton:
David Cameron showed his softer side in an interview on Friday and let slip a crucial personality trait – he is an optimist.
Asked in a Youtube interview to describe one experience that changed the way he viewed the world, the prime minister waxed lyrical about the end of the Cold War.
"I suppose the experience that made me think a lot, politically, was the fall of the Berlin Wall," he said.
"I had spent some time behind the Iron Curtain, I had travelled through Russia beforehand, and I think that incredible year of 1989 was a momentous year. I think so many people had felt that change wasn't possible, and it proved that change was possible; a more bright, democratic future was possible. And there are some echoes with what is happened in our world today.
"So I suppose I am an optimist, I always like to think on the bright side, and when I think of an experience that gave me a great lift in thinking about life and the future of our planet and the people who live on it, actually that year of liberation was an incredible year."
As we face a bleak economic outlook, optimism may well be a useful quality in a leader – as long as it's not misplaced.
The prime minister was then asked if he could ask one question to a world leader, dead or alive. What would it be and to whom?
Unsurprisingly, as a British prime minister the obligatory answer is Winston Churchill.
Cameron said he would ask the wartime prime minister how he kept going in the face of adversity.
"I think if it was anyone ever, I think it would have to be Winston Churchill in 1940, I think the most incredible year in British history when we stood alone and the whole of the world seemed to be against us, with only us standing against Hitler and all of the armies he had amassed," he said.
"I think understanding how Churchill maintained that courage and that fortitude to take his country, my country through that incredibly difficult time – I have read so many books and articles and stories about that period, but to ask him what it felt like and how he kept so steadfast, I think would be fascinating."
Perhaps Churchill was an optimist.