That's it, now it's official. My book about the late Ken Campbell, the maverick director and theatrical visionary who never had an Arts Council grant worth the cutting, will be published on April Fool's Day next year.

The choice of date is deliberate, and not only because it best fits with the sales scheduling of Nick Hern Books. Ken Campbell: The Great Caper (with a foreword by Richard Eyre) celebrates, in part, the great hoax of the Royal Dickens Company which Campbell and his Road Show sidekick Dave Hill perpetrated in the wake of the RSC's runaway success with Nicholas Nickleby.

On 14 July 1980, half-way through the first run of that wonderful show at the Aldwych Theatre, letters, supposedly signed by Trevor Nunn ("Love, Trev"), were despatched to the theatrical great and good inviting them to participate in the renamed national company on new fictitious stage versions of, among others, Little Dorrit adapted by Snoo Wilson and Martin Chuzzlewit in a new version by Alan Ayckbourn: "Let me know your reactions, Peter, together with any plans you might have for altering the shape of the auditorium."   

These letters were typed on RSC headed notepaper, with the official square letterhead of "RSC Royal Shakespeare Company" substituted with "RDC Royal Dickens Company" under the overall direction of Peggy Ashcroft, John Barton, Peter Brook, Terry Hands and Trevor Nunn, and indicated that, for now, at least, the Bard of Avon's time was up.

Posters appeared, wires were buzzing, the box office besieged, and the last night of Nickleby was stormed backstage with special deliveries for Nunn and Roger Rees, who was playing the title role.

A weary, increasingly unamused director, told The Times that the situation had become deeply embarrassing with "a lot of people" writing to him, some refusing, and others (even more awkardly) accepting, his offers of employment.

Not until Campbell appeared on BBC's Newsnight on 4 August and cracked under questioning from Jeremy Paxman, was the hoax exposed. The details of its execution, with brilliant art work and a stream of hilarious paragraphs in the newspapers, guaranteed the jape an unassailable place in theatrical folklore.

Many of Campbell's more bona fide enterprises were similarly madcap and outlandish, ranging from the nine-hour Illuminatus! which originated in Liverpoool and opened the NT's Cottesloe auditorium (with the voice of John Gielgud as a speaking computer) and the twenty-two hour The Warp at the ICA Theatre, right through to his intimate, irresistible monodramas and brilliant television documentaries about psychology, science and parallel universes.

Campbell once described himself as the Peter Brook of the Colchester Rep, and it's this vaudevillian bravura, as well as his distinctive and unusual personality, that made him such an attractive and indeed overwhelming theatrical phenomenon.

There's no-one remotely comparable to him in our theatre of today, which is one of the reasons I wrote the book.

Another was the availability of his well-stocked archive and the prospect of telling his remarkable story with the aid of witness from his peers and colleagues -- Jim Broadbent, Nina Conti, Prunella Gee (his ex-wife and life-long friend), his daughter Daisy, Mike Leigh, Bob Hoskins, John Sessions and countless others.

When I rang Bill Nighy and asked him if he'd talk to me for an hour about Ken Campbell, he refused point blank. "I'll talk to you for ten hours about Ken Campbell," he said. And he did.

Sir Trevor, incidentally, forgave Ken his misdemeanours and indeed incorporated the maestro into his NT schedule with no less enthusiasm than had his predecessors, Peter Hall and Richard Eyre.

For those directors, and indeed for most theatre practitioners, I think Campbell represented the kind of work, and the kind of theatre, they secretly envied and would most like to have seen taking precedence over their own.

In my case, Campbell always reminded me of what appealed to me about theatre in the first place, and I wanted to examine exactly what that was, and why. Which was another good reason, perhaps an excuse, for writing the book, too.