Whose life would you want to write? Whose would you want to read? Biography, we're told, is in a parlous state. The 50 top-selling biographies/autobiographies today are dominated by showbiz celebrities (such as Russell Brand's My Booky Wook), sportsmen and chefs, or misery memoirs. Bucking the trend are Barack Obama, Amanda Foreman's Georgiana (reissued as a film tie-in) and the Mitfords' letters.

To illustrate the gap between critical and popular success, the recently-quoted indicator is that Hilary Spurling's life of Matisse, which won the Costa Prize, had sold 12,000 copies, while Being Jordan, the ghost-written memoirs of the glamour model Katie Price, shifted 335,000. Not really surprising: what's bought and read in quantity reflects the state of the nation. It's like comparing audiences for MTV and Radio 3.

Yet the practitioners of biography, “a hunched and harried crew who have to be prised away from their desks” in the words of one of their number, Kathryn Hughes, persist in aiming at the most discerning readership. Every year the flourishing Biographers' Club holds an award dinner with a single prize: £2,000 (underwritten by the Daily Mail) for a book not yet written, by an untried author. Contenders submit a synopsis and sample chapter. On Tuesday night at the Savile Club, the five shortlisted contenders dined along with veteran biographers (Victoria Glendinning, Philip Ziegler, etc) and a scattering of agents and publishers with ears pricked for the next hot idea. (Last year's winner, Clare Mulley, proposed a life of Eglantine Jebb, social reformer and founder of the Save the Children Fund who died 1928. She was signed up at once and the book comes out next spring.)

Richard Davenport-Hines chaired the judges from the happy perspective of a man whose latest biography - of Ettie, Lady Desborough - has been glowingly reviewed. But glowing reviews don't always herald high sales. Most biographers regard their task as a labour of love (or lunacy), and the judges had been moved, he said, by the “idealism and personal sacrifices that underlay the submissions”. Sadly, many of those submitted would have little hope, in today's commercial climate, of finding a publisher. Commissioning editors are answerable to jack-booted sales people, unimpressed by original ideas or elegant writing.

But there was hope for the few. Katie Waldegrave, 27-year-old daughter of Lord Waldegrave, submitted a convincing proposal for a study of Dora Wordsworth and Sara Coleridge, daughters of the poets. It would embrace the influence of fathers on daughters, the legacy of fame, drug dependency, eating disorders and Victorian women's subjugation. Promising.

Sabina ffrench Blake proposed a life of Henry Tonks, the surgeon and influential Slade art teacher, in an engaging submission: “It had lovely manners,” Davenport-Hines said. Helen Braithwaite wrote a “formidably learned” proposal for a life of Gunpowder Joe - Joseph Priestley, the dissenter and discoverer of oxygen and inventor of soda water.

Edward Black's bravura outline of a life of the Marquess of Bristol, subtitled The Sex, Drugs and Rock 'n' Roll Aristocrat, could expect handsome serialisation rights, but after pondering on Lord Bristol's “gruesome and disheartening” story, the judges preferred the charm and joie de vivre of Michael Bundock's In Search of Francis Barber.

Barber (a familiar figure in Johnson biographies, and in several novels) was Dr Johnson's Jamaican manservant, a former slave brought to London in 1750 at the age of 10: so fond of him did Dr Johnson become that he named Barber as his legatee. An unassailably commercial subject (black history is topical), said the judges - and Bundock is well placed, as Johnson's tercentenary approaches, to produce a book of the mercifully non-blockbuster variety. By day he's a shipping lawyer, dealing with everything from pollution to piracy at his desk in St Paul's Churchyard, five minutes' walk from Dr Johnson's house, of which he is a trustee, a pillar of the Johnson society.

I wish him luck. When Simon Callow, the actor who also writes biographies, spoke after dinner he told of the biographer's trials and tribulations: a vital tape wiped; discovering a Charles Laughton archive only after correcting his Laughton proofs; a Mrs Rogers, secretary to both Laughton and Orson Welles, who went blind before divulging the contents of her indubitably fascinating coded diary.

Callow has spent 20 years so far on Orson Welles, “an almost inexhaustible subject, complex, contradictory, a man of so many different gifts and impulses: to find the one person inside is almost impossible”. His first two volumes, 1,200 pages, have taken Welles, who died at 70, to the age of 32. With interruptions such as playing Captain Hook in pantomime this Christmas, Callow is at work on Volume Three, where (ignoring Welles's serial but “irrelevant” amorous escapades) he will reveal “the two loves that were crucial to an understanding of him”.

Michael Holroyd, playing devil's advocate in The Case Against Biography, quotes Wilde: “It's always Judas who writes the biography”. But that's plainly not true of the Biographers' Club coterie, sifters-out of hearsay, anecdote and provable truth, devotees of solipsistic diarists,writers, scholars, talkers, adventurers, sinners and bounders.

If today's instant celebrity blurs the distinction between fame and genuine worth, another pitfall is instant oblivion. Andrew Lownie, the literary agent who until recently ran the Biographers' Club, says: “I just know that if I sent a publisher a proposal for a life of Edward Heath, someone would say, who? I heard recently about a publisher who asked, ‘Winston Churchill - is he still alive and will he sue?'”

An interest to declare. Having embarked on a biography of Kaye Webb, I long to hear from those who met Kaye, especially members of the Puffin Club, which inspired so many writers, artists, publishers and indeed biographers. vgrove@dircon.co.uk

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