"Shall we go outside? You won't have too much to carry?" he asks, immediately solicitous.
Renaissance man, polymath, universalist, Jack of all Trades ... Jonathan Miller's astonishing capacity to move from one world to another has both inspired and, at times, alarmed. It seems to rather surprise him. "I suppose it is true, my life does resemble a butterfly's existence, moving around from one flower to the next," he says ruefully. "But of course butterflies do pollinate. There is a point to their activity. I hope there is to mine"
Miller's parallel lives as a neuropsychologist and stage director are well-known. But recently he has made a foray into another world. He has just finished curating his first art exhibition, Mirror Image for the National Gallery, which opens this week.
Miller's evident passion for life and people is instantly infectious. His flow of conversation is interspersed with impersonations of the trendy television producer or the art lover: "My dears, did you see the Massacios? They were wonderful!" One is reminded that it was as a stage performer Miller first became famous, almost 40 years ago in Beyond the Fringe.
His peculiar charm lies in his attentiveness and interest in everyone around him. "I have to say I'm very in awe of you as an art historian," he flatters.
"The English have always been suspicious of me," he says. "Alan [Bennett] is somehow much more acceptable. I've always been more of an outsider."
Miller is known for his sensitivity not so much to criticism, but to the critics. He has had his share of bad press and does not pretend it doesn't upset him. "I try and avoid reading reviews these days, but even that doesn't always work." We discuss how and why art criticism, indeed most forms of criticism, remains a male preserve, even in the Nineties. "That whiff of testosterone as they go in for the kill is unmistakable," says Miller. "The best writers on art, or theatre and opera for that matter, are the ones with less of an axe to grind and less of their own ego involved."
The idea for his exhibition, "Jonathan Miller on Reflection", came from a series of lectures Miller gave for the National Gallery on "Looking", a subject which fascinates him. It is partly his interest in psychology that triggers his interest in art. He is especially interested in body language and how this is represented in art.
"The way that we look at each other, or avoid looking at each other communicates on all manner of levels all the time and is constantly revealing," he says. "I also like the intellectual problem of how you go from the appearance of things to the representation of the appearance of things ... What representation really is."
The exhibition clarifies the human capacity to recognise real life mirrors as well as those in paintings - a complex psychological process of which we are normally unaware. The young child's first delighted recognition of himself is captured in the show by George Romney in his portrait of Mrs Russell and Child.
Miller and his wife of 40 years, Rachel, a retired GP now in the medical research field, have recently become grandparents to Rosie and her baby sister. This has re-awakened his interest in child development: he watched transfixed as Rosie started to notice herself in the mirror. He clearly dotes on them. "I remember an American friend's joke about having grandchildren. 'Why didn't we do it this way the first time?' It is wonderful to watch the growing up process again with the eye sensitised by the previous exposure, but relieved of the pressures of caring.".
Visitors to Mirror Image will be able to examine the optical effect of real windows and mirrors as well as the reflective illusions produced by artists. They will also be able to walk through a corridor of windows and mirrors to experience the sensation of "the Looking Glass House". "Some of the paintings in the show are about vanity, like the follower of Leonardo's Narcissus," Miller says. "But of course looking in mirrors is not only to do with vanity. It can be more psychological, to do with reassuring ourselves of our existence or our own place in the world.
"I think my interest in looking at paintings was initially very bound up with my interest in biology," he says. "At the age of 12, I was given a telescope and from then on I became completely obsessed with biology and thought about it morning, noon and night. Up until that age I think catapults and girl's bottoms had held far more fascination!"
I ask him how he finds the art world in comparison with, say, the world of opera or of neuropsychology? "Well, like everything else it is quite a closed world. But so of course is the theatre - not a world I would care to be in permanently - although I enjoy the tantrums and grease paint for a while."
"Art history is fascinating, but the worst of it is that it can become a game in its own right. The other regrettable aspect about the visual arts, in comparison with the other arts, is the peculiar snobbishness attached to it."
At 63, Miller says that he does not think more about mortality now than before, although he believes that he has become wiser. "But as a result one can also become sadder and more aware of mankind's terrible failings," he says.
"But that pessimism can always be redeemed by unexpected compassion in other people. Did you see Michael Apted's 42up on the television? One of the interviewees who went to St Paul's, as I did, ends up so much not following the public school boy's path, but teaching in a state school in the East End. But you could see his concern for others developing in him when he was only seven years old.
"It is strange to look back to my own early days in Beyond the Fringe. What is it that Alan and I had or have that has so far helped to keep us from the self-destructive tendencies that took a hold of Peter [Cook] and Dudley [Moore]?" Different backgrounds, I suggest.
"There was really nothing to indicate it then," says Miller. "It is only with hindsight you might see something. It is all about different personalities reacting in different ways to the chances life offers. And although life is so much to do with chance, it is, of course, our own natures, formed relatively early on that predetermine how we react...
"That is what is so endlessly interesting about paintings. The way in which we all bring our own experiences to pictures and interpret them so differently." He looks anxious for a moment. "Oh dear, I keep thinking of things I could have included in the exhibition and the book ... The whole problem of self portraiture, for example - you could stage a whole exhibition around that aspect of mirrors alone ... But you can't do everything, can you?" he asks beseechingly.
No. Perhaps not everything. But Jonathan Miller gets closer than most.
'Mirror Image: Jonathan Miller on Reflection' begins at the National Gallery on 16 September. The book 'On Reflection' by Jonathan Miller will be sale at the National Gallery bookshop.Reuse content