Evidence of my chronic late-adolescent John Fowles fixation lies all over the study shelves: dog-eared paperbacks of The Collector (1963), The Magus (1965) and The French Lieutenant’s Woman (1969); a stout Book Club Associates edition of Daniel Martin (1977) given to me by my parents; a mint-­condition hardback, even, of A Maggot (1985), Fowles’s last proper novel. Well-thumbed and zealously scrawled-over evidence, too, for between the ages of about sixteen and twenty Fowles featured in my imagination as a kind of Casaubon-style key to all mythologies, a figure of – or so it seemed to me – towering sophistication and import who had the inestimable advantage of knowing how the grown-up world worked.

Ten years later, at work on a book about the state of the English novel, I decided to pay Fowles and his oeuvre a second visit. It was an odd experience, in which the memory of youthful enthusiasm and what might just have been classified as a mature judgement uneasily contended, but the verdict, three days later, was inescapable. What had looked like sophistication revealed itself as sleight of hand. What had once seemed pungent aphorisms reconfigured themselves as cracker mottoes. No doubt about it, I said to myself regretfully, laying down The Magus, a novel over whose 656 closely printed pages I had sat enraptured during the final days of the Callaghan Government, this is unreadable.

John Fowles, ladies and gentlemen, who died twenty years ago this month and the centenary of whose birth falls early next year: what went wrong? How could a writer who was seen as a titan of the world novel half a century ago, ranked alongside Calvino, García Márquez and Kundera,