Marcus Sedgwick relaxes with a gem from Terry Pratchett

There’s a moment as a reader, not often enough felt, when you sigh comfortably and relax, because you know you’re in good hands. Such a moment occurs commendably near the start of Dodger – in fact, in the very first chapter title, in which the author teases us with the notion that he is going to introduce one of the greatest British novelists to one of his best-loved fictional creations. Can it be true? Yes, for here in the opening pages of the novel, Dickens himself, known as Mister Charlie, encounters a young man known only as Dodger, as the scallywag rescues a damsel in distress from the brutal clutches of her foul husband’s henchmen.

A move such as this is the hallmark of a confident writer; it takes not only daring to do it, but skill, and from the first exchanges between the pair, you know it’s going to work.

The girl, known only as Simplicity, has escaped the torment of her loveless marriage to an unknown nobleman “from one of the Germanys”, but she remains in mortal peril. Dodger and Mister Charlie agree that they are best placed to safeguard her life. In doing so, Dodger inadvertently begins to rise up the ladder of Victorian society “faster than a chimpanzee”.

Though the plot of the novel is relatively simple, there is as much pleasure in seeing Dodger charm, sneak and sometimes bash his way in and out of a series of dark and dangerous encounters as he seeks to protect Simplicity, as there is in reading Pratchett’s prose. Here, once again, is the mark of a great writer; that we are captivated by ingenious word-building on every page.

In the author’s note, Pratchett admits that this is a work not of historical fiction but of historical fantasy. Yet it’s founded on the well-known fact that Dickens based many of his characters on the weird and wonderful people he encountered, particularly during his less than fortunate upbringing.

So, along with Dodger we meet his Jewish jeweller landlord Solomon, modelled on “Ikey” Solomon, widely held to be Dickens’s inspiration for Fagin. Appearances are also made by young “Ben” Disraeli, Joseph Bazalgette and Henry Mayhew, whose groundbreaking work London Labour and the London Poor Pratchett acknowledges as the foundation of his novel; perhaps one could say the sewer that runs underneath it, for the dark and malodorously fluid subterranean life of Victorian London forms a major part of the book.

Prachett’s game-playing abounds; he introduces Sweeney Todd to the story, gleefully paying no heed to the twin facts that the Demon Barber is not only fictional but hadn’t even been written at the time. There are some lovely jokes surrounding Dickens. When Dodger worries that Simplicity will be shut up in some bleak house, we can almost see Mister Charlie snatch his notebook from his pocket and fumble for a pencil, with that faraway look writers get once in a while. And then there’s the name of Solomon’s dog. At this point, your open-mouthed reviewer found himself thinking, no, he can’t have called it that – surely the editor would have taken it out. Perhaps it only survived redrafts through naivety in the editorial department, and yet, upon my word, here’s the author in the closing pages inviting us to google what Onan means …

As Dodger’s triumphant path ultimately brings him honour from the very highest rank of society, we cannot help but cheer not only for his success, but also for the success of this ebullient, funny and delightful novel.