It is brave of the Parish Church of St Mary the Virgin in Primrose Hill to welcome Dr Jonathan Miller. The title of the talk by the veteran doctor turned humourist, opera director and TV presenter is: “Is one God dangerous? An atheist’s view of world faiths.” It is the last in the series of lectures that the London church holds each summer.

Ironically, the proceeds from the £10 ticket price go towards the work of the Anglican church’s youth leader. An anti-God rant is funding the propagation of religion. Miller doesn’t get a fee but he gets to plug his latest works: a book on Darwinism and a BBC series on embryology.

The Reverend Robert Atwell introduces the learned doctor. The two men stand under a crucifix of a fully robed Christ. “Let it never be said that here in St Mary’s we are not open-minded,” says Atwell, to chuckles.

The 200-strong audience are mostly over 50 and nearly all white. Pearls and tweeds are not out of place. Miller is dressed in a casual navy linen jacket, ivory slacks and an open-necked, sky-blue shirt. His spectacles hang on a cord around his neck, where they stay. He looks his 71 years.

He reveals that the title of the talk was not of his choosing. He would like to talk more generally about “disbelief” - last year he did a series for BBC4, A Rough History of Disbelief. He is “reluctant” to call himself an atheist. (”It scarcely deserves a name. There are hundreds of things in which I do not believe but which I do not have to find a title to account for my disbelief. I don’t believe in witches. I don’t believe in fairies.”) He also despises the “cowardly and feeble” term “agnostic”, which he says people often feel happier to adopt as if the word “has a conceptual condom around it”.

Miller’s notes-free delivery is casual, chatty and laced with comments that raise a titter and the odd eyebrow. His tone is learned but a little hectoring and, for those who do believe, possibly verging on arrogant. His satirical dismissal of the beliefs of many of the audience as “nonsensical”, “meaningless” and “not buttering any parsnips with me”, brings looks of dismay.

He talks of the history of atheism. “Until 250 years ago, atheism was an accusation rather than an identity.” As late as the 17th century in Britain, a man was hanged “for affirming disbelief”. He recalls his own personal history: how, as a child, “the notion of a deity never occurred to me at all”.

School prayers meant no more to him than “lewd” playground rhymes. He suddenly quotes one: “Temptation, temptation, temptation. Dick Barton went down to the station.” There are bemused looks from the audience and a few polite laughs. Later, he talks of seeing his nanny praying at night while getting undressed, and the “rasping of elastic”.

Behind the wooden lectern, he bounces on his toes and gesticulates as he recalls his days at Cambridge University. Here he became interested in “ontological issues” and philosophy with a biological twist.

With his teacher, he discussed involuntary and voluntary movements and “sub-intentional actions”. He points out his own, now increasing, hand movements as an example.

To the man who wrote and presented the TV series The Body in Question, life is solely physical. He rubs his thinning white hair. “Bodies make us what we are and we are inconceivable without bodies.”

He talks a lot of “intentions” - how humans are always looking for a reason for being. But Miller can’t explain this. “Intention is a late arrival in the history of the universe,” which only exists when there is life. “To say that life itself is created by something that has intention is to create a deeply vicious conceptual circle.

”Looking for a disembodied creator of bodies is as absurd as it would be to look for a circular rectangle.”

When it comes to the meaning of life, he freely admits that he hasn’t the faintest idea. He is not interested. Rather, he is “a passionate addict of the negligible”.

He winds up his half-hour talk. “I do not believe that atheism or disbelief requires any proof at all.”

Afterwards there are multitudes of questions, some indignant, many in the same vein. How does he explain miracles? Superstition? Consciousness? Morality?

He slaps his palm as he says passionately that when it comes to things that science doesn’t know, “God is not an explanation.” He jokes about “the clergyman in the laurel bush” who pops up whenever something seems inexplicable.

”Our appetite for seeing the extraordinary is because we’re so bored with the ordinary.” We should be satisfied with what we’ve got. Life “ends with dying and that’s pretty damn good because it brings some sort of urgency as to why you’re here. Imagine what it would be like if there was never going to be an end to it!”

The Reverend thanks the doctor for “coming into the lion’s den”. The lions haven’t touched him. It’s a miracle.