It was just clear to me that this was what people did who wanted to belong completely to God You see, they didn’t have any other – close – loves So I was lucky. But I never heard either parent speak unkindly of anyone.It was a shock when I went out into the real world and found that childish behaviour doesn’t stop with childhood.Becoming a nun was not a matter of traumatic soul-searching “I always wanted to be a nun, as long as I can remember I can’t remember choosing to be one My parents weren’t especially religious But there were nuns at school, where I went when I was four. I can remember telling my sister, You mustn’t look…”Were they a happy couple? “My father thought he’d won one of life’s prizes, to have my mother He thought she was wonderful. I never knew grown-ups quarrelled or spoke harshly to each other I never knew it at home Children quarrelled and were mean. So we got on the train with Daddy – and when he got off at the station, my mother was waiting for him. “I was at boarding school with my younger sister, and the train went through our town. “My father had a late vocation to be a doctor, and we didn’t return until he’d got his degree I was eight, and we lived outside Johannesburg.

Then war came, and my father was medical officer to the Air Force, and we went to live in East London, my mother’s town on the south coast.” Her father returned from the war when she was 15 and about to enter the convent She remembers it vividly. the teeth do make it easier,” she concludes shortly.On an impulse, I ask: have you ever been in love? She shakes her head “I became a nun at 16 It was 1946, you must remember, and we didn’t meet any boys. And also, I was an extremely unattractive child, and I don’t think it would even have entered my head that…” The rest hangs in the air Like all the best English eccentrics, she is a foreigner. She was born in Johannesburg in 1930, and traces of a Serth Efrican accent appear the more you talk with her The family decamped to Edinburgh when Wendy was two. Emboldened by their example, two ladies d’un certain age come up to talk. “We didn’t get selected this year,” says one, an aspirant Academician, sadly Wendy signs her catalogue. The second lady, with what seems to me astonishing cheek, proffers a page on which she has been drawing a likeness of the celebrity nun.

Head bowed humbly, Sister Wendy inspects its bland lineaments “Hmm… She complies, like the Reverend Mother she used to be; but her handwriting is tiny and unnaturally clear, like a ten-year- old girl’s. Viewers found their attention directed to the “lovely, fluffy pubic hair” in a Spencer portrait. And when a journalist once archly referred to “naughty bits”, she rounded on him for criticising God’s handiwork. Standing at the RA before John Bellany’s Bounteous Sea triptych, with its clutching lovers, its blank- faced temptresses and phallic parrots, you feel no embarrassment in her company, but discern a faint whiff of disapproval, possibly of the painter’s technique: “The sexual imagery, yes… I was afraid that I wouldn’t find a way of telling people how great it was. That and Las Meninas by Velasquez; you can hear it in my voice, that I’m overwhelmed, and struggling to keep going…”Which brings us to sex.

There’s something about Sister Wendy that makes people (and television producers) determined to shock her – to take this mumsy, smiling nun and plonk her in front of a Lucian Freud or Stanley Spencer study of sagging flesh and coiled penises and say, in effect, “Talk your way round that, then.” It’s never worked. I was trembling to think I wouldn’t be worthy of it.” Come again? “I was shaking. “We travelled all over Europe for the series, and to America, and as far south as Luxor in Egypt. And we went to the Czech Republic to see the greatest Titian in the world, The Flaying of Marsyas.

“All the major painters are in,” she assures me, “represented by a single work; although an absolutely marvellous painter, a double first like Titian or Rembrandt, gets two.” What was she doing it for? “I hope people will get the encouragement they need to understand how paintings work; but it’s also a story – it’s about what happened next.” Why did she want to make art more accessible to people? “Because it’s their heritage If people want to enter into this world of… limitlessness [a favourite word of hers] that is there for them, it’s up to them what they do with it. Whether they want to pay the price for entering that world – you can’t really receive art unless you’re prepared to give it time and attention – is another matter.” Her own passion for art, focused, indeed marinated, through years of silent contemplation in a Norfolk garden, is a glowing and palpable thing She seems never to tire of the familiar. (“People,” she tells me, “always smile at nuns.”) Watching Sister Wendy posing for her photograph, head canted forward in an attitude of sweet innocence, eyes spaniel-like with passivity, hands clasped like St Theresa of Lisieux (the “Little Flower”), you think: here is a strong, clever woman who really can take or leave the world, and who leaves it wanting her back again.Her new television series, Sister Wendy’s Story of Painting, which starts on BBC1 on 30 June, scampers through the history of art, from cave paintings to Francis Bacon, in ten half-hour talks. I read it the next day for the obituaries, which I find fascinating.” Does she keep up with the news? “No.” (Her political stirrings are summed up in the words “That nice Mr Major” or/and “That poor Mr Blair”.) Does she watch television? “The convent doesn’t have a television.” Does she go to the cinema? “Never.” How much is a pint of milk? “No idea.” What do the words Blur and Oasis mean to her? “Well, I know they’re both singers, but I’m afraid I don’t know any of their songs.”Any temptation to go “Ahhh…”, however, is countered by a suspicion that she is laughing at us, playing to the hilt the kindly, virginal Reverend Mother. Remarking that “one cannot read Dostoevsky all the time”, she will quote Dick Francis at you. Her relish for the world of flesh and blood is theoretically confined to the medium of paint; but for every mention of God, there’s a balancing moment of delight in the ordinary.Her interest in Star Trek, for example, is of a piece with her love of horse racing and her pride in spotting winners; she studies form in the Racing Post, but doesn’t bet.