When he was still talking to me, I did manage to put that to him.
He said, with obliging good humour: "You must have noticed by now! Ha, ha, ha."
He had obligingly put on his Akubra hat for his picture. I'd really wanted to see his famous bowler. A piece appeared under his byline in the Daily Mail about bowler hats, which included this marvellous account (and as I didn't get to ask about that either, this much-edited version will do): "I once forestalled a riot in Whitehall by doffing my hat at just the right moment. During the miners' strike of 1982-83, Arthur Scargill decreed that the miners should descend on Parliament Square in force to lobby members of the House of Commons. At the time I was working at my desk in No 10.
"Oliver Letwin, now a Tory MP and Cabinet Office minister ... came dashing into my room with a look of terror on his face. 'The miners are rioting in Parliament Square,' he cried. ' ... What do we do if they invade the building?'
"'Nonsense', I said, (for I have always had a soft spot for the miners, the heroes of labour). 'This is what they do every Friday night when the pubs tip out in Leeds or Barnsley. I'll go and talk to them.' And I reached for my hat ...
"At the sight of a chinless, pinstripe-suited fop emerging from the Prime Minister's house, the miners jeered ... As I walked towards them, I raised my hat to them and smiled. The jeering instantly turned to cheering - loud, long and happy.
"... I stopped 10ft from the miners, looked one of them in the eye and said (very quietly, so that they all had to listen): 'You have something to say to the Prime Minister. I'll pass on whatever you say to me. You've come a long way, so would you like a drink in the pub across the road?'
"They would. Like schoolchildren with their teacher, they filed amiably across Whitehall to the pub, where I bought them pints of ale and made a careful note of what they said.
"The riot was over - and all thanks to Edward Coke and his gamekeeper."
I have seen a picture of him wearing a pith helmet. Some pictures of him make him look a bit dotty. His friend, Bryan Leyland, who he is staying with and who kindly came and picked me up, said that he was a "showman" and that because of illness (Graves' Disease) he has popping eyes and so some people mistakenly think he's a fool.
He gives a good impression of a chinless, pinstripe-suited fop, and eccentric English toff. I said: "What is your public reputation?"
He said: 'I don't care."
I had said, earlier: "How shall I describe you?"
"I'll let you do that." And then I'll get one of his letters? "No, because I think you'll be fair. I hope that you'll be fair." He may not care about his public reputation but he threatens to sue at the drop of a hat, bowler or otherwise. So I won't attempt to describe him and really there's no need - the story of the bowler hat and the foiled riot does a better job than I or anyone else could ever attempt.
Like many people who give a lot of lectures, he regards an interview as a lecture with an audience of one, and any but the most anodyne of questions as hostile heckling.
He is also what you might call a long talker. So, if you ask, as I idiotically did, how his health is now, 10 minutes later you will not have a definitive answer to that question.
Although I am in full agreement with the specialist who said he was the most fascinating case he'd ever seen. The story, or part of the story, is about how nobody could figure out was wrong with him and so he did a mathematical diagnosis of his symptoms and exhaustive amounts of research and - after much going back to specialists - came up with a "preparation" which might help and which was then denied him by the NHS and so ... he made it himself. What, in the kitchen? In the library, at home, as it happens.
"I got some eye of bat and toe of newt ..." Then he couldn't get the stuff to "go to solution" so he put it in the loch at the bottom of his garden and it did whatever it was supposed to do and then ... "And then you took it?" I said, hopefully, seeking a cure as an answer.
"No, no, no. Of course not. I wrote up the lab notes and sent them to the surgeon and said: 'Look, am I going to kill myself?' So he rang up five minutes late roaring with laughter and I said: 'What's the point here?' He said: 'I've just been reading your lab notes.' And I said: 'These are serious lab notes!' He said: 'I know, but they're terribly funny!"'
I can't tell you what the stuff was because "we've patented it and until we've published the patent I'm not allowed to discuss that".
Well, really! This was the equivalent of somebody telling you a 10 minute-long joke and then refusing to reveal the punch line.
But the real point of this story is that the surgeon said, after reading the terribly funny lab notes: "That's how science used to be done."
Is he a scientist? He says he was a science adviser to Margaret Thatcher. John Gummer, who was Thatcher's environment minister, has sniffily said that he was "a bag carrier in Mrs Thatcher's office". He says Gummer is chairman of "several wind energy companies and has a very large vested interest". In what? "In discrediting those who have pointed out that wind energy makes no economic sense whatsoever and no environmental sense either."
He said: "What I am is a mathematician." He read classics at Cambridge and studied classical architecture so, "naturally I had to do various branches of mathematics ... You didn't want your buildings falling down".
He invented a puzzle called the Eternity Puzzle which offered a million quid to anyone who could solve it. When it became obvious it was going to be solved, he put Crimonmogate, his 67-room house in Scotland, on the market. I thought he'd later said this was a PR stunt and that he was going to sell it anyway, but he says no, somebody else said it was a PR stunt. "Of course I could see the advantages of selling the house because this would naturally mean that people would realise I was concerned the prize might be won and they'd all rush out and buy puzzles - which is exactly what happened." So it was a PR stunt? "No. It had PR advantages."
I'm not sure how good he is at PR. In 2008 he wrote an open letter to senator John McCain which included this: "His contribution to the IPCC's Fourth Assessment Report in 2007 - the correction of a table inserted by IPCC bureaucrats ... earned him the status of Nobel Peace Laureate. His Nobel prize pin, made of gold recovered from a physics experiment, was presented to him by the Emeritus Professor of Physics at the University of Rochester, New York, USA."
This was a joke. And "the most charming gesture". I didn't think he'd quite laid out the joke bit in his letter. He couldn't remember exactly what he'd written and as I didn't have a copy of it and as he didn't either: "We can't take that one any further forward, can we?"
I did try and he said, crossly, that I should speak to the professor. He wasn't there. "Well, there are things called telephones. You may not have them in New Zealand. We've had them in Britain for 100 years."
He says that when he began writing about climate change he was "immediately and very savagely attacked ... in a manner which seemed to me to be disproportionate and unreasonable and unfair". He "began talking to others who shared my doubts ... and they were being subjected to the same things. So then I tried to see whether we were doing it back. And not really. Not to the same degree".
Ahem. There was the episode with the youth activists in Copenhagen. He called them members of Hitler Youth. No, he didn't. I didn't happen to have the You Tube clip with me, so I amended this: He said they were being like members of Hitler Youth.
He said they had disrupted a private meeting and an old German man burst into tears and told him he'd been in Copenhagen when the Nazis invaded and "this is how they broke up meetings".
But my point was that he persisted in the Hitler Youth analogy even when one of the activists told him he was Jewish. We went back and forth on this for a bit until he said: "Let me finish. You don't interrupt or I'll end the interview." And did.
At the very beginning I had asked what was the correct way to address him?
He said: "Well, you go down on one knee, put on your white gloves, touch your forelock, bow a little and you say: 'My lord, would your lordship be so gracious to allow me to address your lordship?' It's really very informal. Ha, ha. Call me Christopher. It's the easiest thing."
The forelock tugging was a joke, obviously, but I can't help thinking his lordship would have preferred a little more of that and a lot less of the pesky asking of questions. It's only fair to say it was all my fault for mistaking an audience for an interview.