Suddenly it's me, I'm there, close enough to kiss him. 'Who to?' he grins, his hand - that actual hand - poised over the book

We sit in the National Theatre's hushed, plum-carpeted, concrete foyers drinking stewed, pointless coffee and dissecting the world's most expensive rectangle of chocolate cake with a white plastic fork.

"So," Jonathan peers into the carrier bag containing most of our cherished collection of John Updike, "which do you think?"

"Let's see what the queue's like," I say, stealing the bit with the most chocolate fudge stuff on the top, "Play it by ear."

It's a tricky one. This writer, this god who can lay words next to one another as if he personally invented the language, has come to talk for 45 minutes and sign books afterwards. We read, love and collect him; we want his mark on our volumes. But which? It would be easier to take him home with us and present our sitting-room shelves and say, "OK, John, go to work."

We both agree that six books each would be too many - an imposition, an embarrassment.

"If the queue's short, three might be all right," I begin.

"It won't be short," says Jonathan.

I always did push it. At the age of 12, I wrote to Roger Lancelyn Green - that vivid re-teller of legends for children - telling him I had decided to become a novelist. He wrote back and wished me luck, cheerfully confessing that it had taken him 10 years of trying before getting published. Unabashed, I wrote back to say I expected to be published by the time I was 16. He responded, informing me that he'd written 60 books in 30 years.

Did that put me in my place? Not a bit of it. In 1975, I ditched Roger for Daphne - du Maurier. My mother and stepfather had a boat in Cornwall and I devoured her novels (fat, yellow library books) one by one, lying on the clifftops at Polruan - or holed up in the diesel-fumed cabin of the boat whilst it poured with rain outside.

Back in Nottingham, I went straight to my typewriter. "Dear Daphne ..." I sent her a sheaf of my poetry and asked her where I should send it.

"I'm not very well-placed when it comes to poetry," she wrote. "But I liked yours. Good luck with your O-level exams."

I did not leave Daphne alone. I now have a chocolate box containing a bunch of postcards and letters from her.

"How nice to hear from you again," she writes. "And well done with your O-level results ... thank you too for the drawing (of my cousin Rachel), which is more attractive than the actress, Olivia de Haviland, who took the part in the film! Good luck with your novel, do persevere with it."

(I was writing Samantha: A Tale of Love and Intrigue, heavily and unashamedly based upon her own immortal Rebecca).

"How nice to hear from you again. This is my house at Par, which appears in my novel The House on the Strand. I hope you'll be able to live in your dream home one day - Menabilly was mine, but I've settled very happily here."

Finally, I have a lovely, signed photo of Daphne sitting just where she ought to sit, on a Cornish beach, staring out to sea with writerly wistfulness. She's wearing a rust-coloured shetland jumper and a brown waistcoat and brown flared slacks. I used to scrutinise that photo, stare into that face, admire that perfect square jaw, that wind-whipped grey hair.

At 16, still unpublished, I dropped a line to John Betjeman, enclosing my poems.

"How nice of you to write to me!" he exclaimed, in handwriting that crawled satisfyingly over the page like a live insect. "Your letter arrived just after breakfast at a time when poets are generally feeling low."

He went on to give me a generous and meticulous critique of my poems and rather rashly assured me that I would be published; all it would take was a little time and patience.

I've never written to Updike. We file into the Lyttelton Theatre and there he is, puck-faced and white-haired, centre stage. I drink him in - his face, his fingers, the shape of his head - trawling for clues, for the novels which are never there when you look.

When he's finished reading - a performance punctuated by endearing giggles, laconic asides - he answers questions ("I understand you like them over here").

"What hours do you work?" demands a serious boy with glasses. It seems a funny, pointless thing to ask, like "what are your bowel habits?" Normal hours, is the gist of Updike's reply - except for things like dental appointments.

I don't ask anything. I spectate, open-mouthed.

"OK," says Jonathan, in the queue afterwards, "just two each." We shuffle and select. Suddenly it's me, I'm there, close enough to kiss him.

"That was lovely," I whisper so he can't hear.

"Who to?" he grins, hand - that actual hand - poised over the book.

I flush, tell him my name.

He writes, scritch-scratch, closes the books, hands them back, already making eye contact with the next person.

Jonathan and I walk into the concrete South Bank heatwave with our bag of books - the signed and the unsigned.

"You should have brought yours," says Jonathan suddenly.

"What?"

"Your book. To give him."

"Oh no, no way, I couldn't."

"Why not?"

"Well, he wouldn't want it. He wouldn't want to carry it around." This man is God. I blush at the very idea.

"Well," says Jonathan with unusual and touching loyalty. "I think you should have. I ought to have made you."

I shake my head, still pink at the thought. I'm not like that. I don't just throw myself at famous writers. Not any more.