Deeply entranced

What makes a novel a Victorian novel? To have been written during the Queen's reign helps, but isn't crucial. After all, some Victorian novels were not especially conscious of being Victorian novels, so busy were they telling their stories, whereas novelists writing now about the period know better what's expected of them. Then there are the novels (Jude the Obscure, say) that seem to belong to this century, not the last - and the novels from this century that behave like Victorian novels, in all their tropes. Perhaps a distinction needs to be made between Victorian novels (Dickens, Mrs Gaskell, etc), Victorian novels (saddies like Jeffrey Archer, a century behind his time) and "Victorian" novels (pastiches or homages like A S Byatt's Possession or John Fowles's The French Lieutenant's Woman, books from which a generation of students has learned more about the genre than from the genre itself).

Peter Carey's Jack Maggs belongs to the third category. It opens in March 1837, the year Victoria came to the throne, with the arrival in Dover of the eponymous hero. Fellow passengers on the coach to London find it hard to tell what manner of man he is, though his hawkish eyes and two missing fingers on his left hand are a clue - as is his habit of addressing men as "mate" and women as "Judy". Posing as a footman, Maggs is employed by Percy Buckle (a former grocer). The other servants aren't fooled: they think Maggs must be secretly distinguished; the maid, Mercy Larkin, goes further and falls in love with him. Under strain from the imposture, Maggs collapses while serving at dinner, afflicted by inner demons and a nasty tic in his cheek. When he recovers from his trance, he's terrified to find he has been talking. The terror is that he has betrayed his secret: that he's a convict, returned from New South Wales.

The secret has been half-unlocked by one of the dinner guests, Tobias Oates, a restless spirit who shares equal billing with Maggs, much as Oscar did with Lucinda in Peter Carey's Booker-winning novel of 1988. Oates is a novelist and journalist, but also a keen amateur mesmerist, adept in the theory of "animal magnetism" popular in the 1830s and 1840s. Offering to hypnotise Maggs again the next day, he promises to rid him of the phantoms and hobgoblins that "live inside your head like beetles in a fallen log". His real motive is more self-interested: he thinks Maggs can give him insights into the Criminal Mind, insights that will make him a novelist greater even than Thackeray.

Maggs is suspicious: he doesn't want his soul excavated. But a Faustian pact is made. Maggs agrees to be mesmerised by Tobias, to go Down Under into his past, if Tobias takes him to "the thief-taker", the one person who (he thinks) can find his long-lost adopted son. The son, Henry Phipps, is now a grown man, for years the foppish beneficiary of the wealth Maggs acquired through canny but honest toil in Australia after being pardoned.

The odds are stacked against Maggs. Phipps, snotty and fearful, doesn't want to see him. Percy Buckle, at first protective of Maggs, because his own sister was transported, begins to regard him as a rival for Mercy's affection. There's the constant fear he'll be discovered and banished. He has only Tobias Oates on whom to lean.

And Tobias, for all his prodigious writing output and scientific curiosity, is a mess - manipulative, exploitative (he has already begun work on a book to be called The Death of Maggs), desperately short of money, and with a dreadful secret of his own: he has been having an affair with his wife's sister, Lizzie, and now she is pregnant. As the two men go to Gloucester for an abortive and bloody meeting with the thief-taker, Tobias entrusts Maggs with his secret. So far he has had the upper hand. But now, as Maggs puts it, they are "bogged" together, mired in mutual dependence like Pozzo and Lucky. Soon they are literally manacled. As they return to London for the denouement, it is Maggs who has assumed control.

Even those with a sketchy knowledge of Dickens will hear echoes of his life in Jack Maggs. Like Tobias, Dickens was interested in, and practised, mesmerism. In May 1837 he was 24, had a baby son, and had been writing for The Morning Chronicle (as does Tobias, who is 25). Most crucial of all, in that month his sister-in-law died suddenly and mysteriously at 17 (she was called Mary, but here becomes Lizzie, while Mary is made the name of Tobias's wife). Dickens's grief at her death was boundless (he even, for the only time in his career, missed a deadline), and there has occasionally been speculation by scholars about the more than brotherly love he may have felt for her - speculation to which Carey gives flesh.

Carey builds on Dickens's work, too. Maggs has given Phipps money because he's grateful for an act of boyish kindness and sorry for him being an orphan - which takes us back to Great Expectations, where the mysterious donor, Magwitch, is an escaped convict and the boy-beneficiary is Pip. Dickens once began work on a novel provisionally entitled Mag's Diversions (about a character called Thomas Mag), which later became David Copperfield. There are many other Dickensian resonances: in the names of the characters, in the evocation of London, in the tales of thievery and artful dodging, in the metaphors and more especially the dialogue (" 'I have ob-served,' said Hawthorne, 'how the two parties are Besotted.' ") The effect isn't so much parody as remix.

Does the remix succeed? Peter Carey did something similar in the first part of Oscar and Lucinda, where he drew on the self-documented childhood of Edmund Gosse, and here again he's upfront about his poetic licence, declaring in a prefatory note: "The author willingly admits to having once or twice stretched history to suit his own fictional ends." On the face of it, the method works well enough: you don't have to know anything about Dickens to enjoy Jack Maggs, and if you do there's the extra pleasure of going back to the novels, or to a biography of Dickens. But Thomas Hardy once complained of the "infinite mischief" in the "mixing of fact and fiction in unknown proportions", and even the most postmodernist reader may be distracted occasionally by a dour Hardyesque voice asking questions about what exactly has been invented - and why.

The why is the more interesting question. Carey isn't writing surrogate history or biography but asking questions about authorship, ownership and theft. Tobias thinks he can use Maggs, because he's colourful, criminal, larger than life; many writers - not just Dickens, not just other Victorians like Mayhew - have worked in the same way. But Maggs refuses to be a Character in someone else's story. He is writing his own story (of which we get generous extracts), and though paranoia and secrecy force him to write back to front and in invisible ink, the words are his. Reading what Tobias has written about him, he feels cheated, pickpocketed, burnt alive. So when he hurls Tobias's notebook into the River Severn, it's a kind of victory for the silenced and marginalised. Many themes in the book - mesmerism, master-servant relations, Tobias's treatment of his sister-in-law, Buckle's of Mercy Larkin - come into the same orbit, of power and abuse. Jack Maggs, in this respect, becomes a kind of post- Marxist, post-colonialist, post-feminist remake of the Victorian novel.

But if this is the intellectual framework, the texture is altogether less conscience-laden. Carey delights in Dickensianism and all its affectionate condescension, cartoon humour and broad farce. His Victorian London may be brooding and claustrophobic, with none of the light or poetry that shine from the New World of Oscar and Lucinda, but the manner of the telling is never gloomy. It doesn't have the leisure to be. The 91 chapters, and the three weeks they contain, zip past, hurrying us on towards an ending part-tragedy, part-melodrama, part-happy-ever-after.

The cost of the frenetic pace is that we're swept past depths and darkness that would have been worth pausing over, that the Carey of Illywhacker or Oscar and Lucinda would have wanted to explore. Despite its skilled construction, there are also some creaks in the plot. It's not Carey at his haunting best. But he hovers there benignly, an author who, when all's done, will allow Tobias to go on and write The Death of Maggs without Maggs having to die, unhappy or before his time.