Arnold Harvey is waiting for me outside his flat overlooking Clissold Park in north London. With beard, lank grey hair and a large stomach that may be the product of eating too many fry-ups at the greasy spoon next door, he looks like a bucolic version of William Golding. It is his first ever interview and he is nervous, expectant. After a lifetime of what he believes to be academic condescension – or worse, conspiracy – he sees me as a possible source of redemption. This could be tricky.

Harvey, who has written most of his books using the initials AD rather than his first name Arnold, which he dislikes, has been exposed in the Times Literary Supplement as the possessor of multiple identities in print, a mischief-maker who among other things had invented a fictitious meeting in 1862 between Dickens and Dostoevsky. This startling encounter was first written up by one Stephanie Harvey in the Dickensian, the magazine of the Dickens Fellowship, in 2002, and quickly hardened into fact, cited in Michael Slater's biography of Dickens in 2009 and repeated by Claire Tomalin in her biography two years later....