John Walsh meets Sister Wendy Beckett

Art critic, Trekkie and the nation's favourite nun.

Within 30 seconds of my meeting Sister Wendy Beckett, she had lain her head on my shoulder, tears filling her eyes. We had failed to meet at a prearranged spot and she, instead of seething with irritation, had worried herself threadbare that I'd become a pile of chewed-up flesh and twisted metal somewhere on the South Circular road. This is entirely typical of the saintly Sister, in whom altruism and hypersensitivity melt together like honey in hot whiskey. She is, she says, alarmingly tuned into the dark side of human nature. "It's one reason I have to live in solitude," she says. "I can often pick up what's going on inside somebody, what they're really like, and it can be distressing when someone is being cheerful and you're picking up signs that there's something gravely wrong inside them." Was she psychic? "More like empathy. Like the woman on Star Trek, Counsellor Deanna Troi, who came from a race of Betazoids."

Good God. Can it be that Sister Wendy, the Mother Teresa of the art-critical universe, the contemplative hermit of a Norfolk caravan, the least worldly human being to appear on television since Gandhi, is a fan of Star Trek? "I didn't know the programme existed until one night I was in a hotel, waving the magic thing where you press the buttons -" A remote control? "Exactly. And this drama thing came on with a very serious moral message, but delightfully conveyed. And I thought, this is grand stuff, so I've watched it at every opportunity since then..."

We are standing in London's Royal Academy, whose Summer Exhibition has been drawing many, almost entirely hostile, reviews. Sister Wendy is not, however, a nay-sayer: she greets any aesthetic experience with a kind of eldritch glee, her hands extended in a blessing towards the canvas. Standing before Crossing Water to the Promised Land, she goes into rhapsodies about its creator, Albert Herbert, "one of the few religious artists in the country". I look uncomprehendingly at a childish scene of stick figures stiffly negotiating a path between two black slabs of water, and suggest that it looks like a pair of jaws. Not for the first time, Sister Wendy does her kindly smile, her rabbity teeth and bright brown eyes transforming her into an indulgent chipmunk. "It may come out as naive, but there's so much more than meets the eye. You have to look at the strange life of the waters, the little monsters you can see popping up here and here, a whole played-out life in the water. We can certainly pass through, but how much are we missing out by doing so? The artist is suggesting that, though it may all sound very grand - the Promised Land - are we losing out by leaving the waters behind?"

Does she always know what she's looking at when she looks at a picture? "Oh no, no - you have to look long and hard and sometimes it takes hours before you suddenly see it, before a painting will un-veal itself to you." She considers this interesting new coinage. "I mean, reveal itself." Or, of course, unveil itself, like a nun. All the time you are with Sister Wendy, the tension between her two worlds - between the veil and the television screen, between the water and the Promised Land - hangs in the air. As she clutches your hand to walk to the next gallery (she needs, she explains, a "leaner" just as, say, Joan Collins might require a walker), as she talks about love and hope and fruitfulness, it becomes bewildering to think that this warm and comely woman has been a nun for 50 years, lives alone in the grounds of a Carmelite convent, and spends seven hours of every day in prayer and meditation. 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. Remarking that "one cannot read Dostoevsky all the time", she will quote Dick Francis at you. Her use of Fifties slang is hilarious (she remarks that a priest in a picture is dressed in "the full monte"; later, after we have visited a Dover Street ceramics shop to look at a Meissen figurine bought by a rich friend, she assures me it was "an absolute snip"). Gradually you are tempted into a questionnaire. Does she read the papers? "The Sisters get the Independent. 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. ("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. "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. "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. I was trembling to think I wouldn't be worthy of it." Come again? "I was shaking. 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. 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... not very alluring, is it? They -" she scrutinises the breasts on display - "look like puddings or blancmanges. I don't think it's meant to arouse. It's more that the sexual imagery stands for life which presses on despite... The woman blankly confronting this great curving beak, this is what we live in, the chaos, we have to live among death and disaster and the possibility that our lives will come to nothing..."

This uncharacteristically bleak note is interrupted by a trio of coltish young women who have been summoning the nerve to approach Sister Wendy for her autograph. 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. 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... 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. "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. "I was at boarding school with my younger sister, and the train went through our town. So we got on the train with Daddy - and when he got off at the station, my mother was waiting for him. 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. 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. 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. I never had to make choices."

After two hours in the company of this enchanting woman, you begin to understand why she gets letters from people saying she has saved their marriages, inspired them, changed their view of what God must be like. She makes a very good advertisement for the Redeemer. When she goes back to her caravan, is she leaving the real world behind? "Oh no, no, I'm going to the real world. It's far more real to me than the transitory things of the other world. The question put to every human being is how to integrate the two. But I've never felt this world -" she waves a hand: taxis, Union Jacks, sunlight on the Piccadilly flagstones "- as terribly real, because I've got the real world with me, shining through."

But still... I ask what single thing has most influenced her life. "Nothing," she says, "No one person or book or event. Although - if I had to choose one moment, it would be listening to JIM Stewart [the Oxford English don who wrote thrillers under the name of Michael Innes] reading Shakespeare's sonnets. "He was at my viva voce. He and Tolkien." And had she got a first? "Oh yes. In fact it was a congratulatory first. They all clapped as I came in. It was wonderful. Oh, but," her eyes widen in alarm. "You won't write about that, will you? It might seem... boastful"