Rather than deal with something complicated, Western powers found that Gadaffi who had until then been isolated and ignored by the Arab world, fitted the bill of a cartoon villain.

“Gadaffi illustrates, like a flash of lightening on a dark night, just how corrupt, how hypocritical, and how empty of values our middles class elites have become,” Curtis told us. “It was quite shocking to me. It’s just rubbish that he had WMDs. There were no biological weapons and he’d got a a centrifuge but none of his people knew how to put it together – it was in boxes.”

But after being demonised in the 1980s and 1990s, Gadaffi finds himself rehabilitated.

“After the Gulf War all these people go out and make him into a modern thinker: David Frost, Anthony Giddens, even Lionel Ritchie went out there, and said Gadaffi was good. Then, after they Arabs Spring he was a villain again, so they just dropped him.”

“I was thinking of making a sort of comedy…

For Hitler, though, a crisis was coming. When the factories where Pervitin and Eukodal were made were bombed by the allies, supplies of his favourite drugs began to run out, and by February 1945 he was suffering withdrawal. Bowed and drooling and stabbing at his skin with a pair of golden tweezers, he cut a pitiful sight. “Everyone describes the bad health of Hitler in those final days [in the Führerbunker in Berlin],” says Ohler. “But there’s no clear explanation for it. It has been suggested that he was suffering from Parkinson’s disease. To me, though, it’s pretty clear that it was partly withdrawal.” He grins. “Yeah, it must have been pretty awful. He’s losing a world war, and he’s coming off drugs.”

It’s a strange experience, walking the streets with this bearded compendium of knowledge. Every corner provokes a reminiscence, such as the graffiti which he recognises as the work of Bill Drummond of art-pop group the KLF, who came round to his house to show him the film of them burning a million pounds. Do they regret it now, I ask?

“It’s not so much that they regret it, but I think it haunts them. I heard a brilliant definition of haunting: ‘That which haunts us is that which we do not or do not completely understand.’ And I thought, that makes sense. Often we don’t understand our own actions. And certainly, if we’d gone to the Isle of Jura and burned a million quid, we would have a lot of questions!”

LD: Here’s what I’ll have: split-pea soup and white-bean hummus. Is that okay?

PUBLICIST: Whatever you want.

LD: And I don’t need the cheesy croutons. And if there’s cream in the soup, don’t get it.

PUBLICIST: I’ll check.

LD: Yeah. No cream or butter in the soup or the hummus.

SR: Is that a lactose thing or a general-health thing?

LD: General health.

SR: So you tolerate lactose.

LD: I tolerate lactose like I tolerate people.