Un Lun Dun By China Mieville Macmillan Children’s Books pound;12.99 10-plus

Darkside By Tom Becker Scholastic pound;6.99 12-plus

Den of Thieves By Julia Golding Egmont pound;8.99 10-plus

As well as being a city with layer upon layer of history, London is a city of contrasts, the shabby and the shady just a whisper away from the smart and the affluent. This makes it easy to imagine other worlds just around the corner or under the surface.

Two recent novels attempt to do just that, each creating an alternative universe with a Gothic flavour. China Mieville’s novel is a curious and intricate narrative that follows the fortunes of two schoolgirls, Zanna and Deeba, who stumble across a parallel “UnLondon” where all the city’s lost and discarded things have ended up. Tower blocks are made out of discarded computers and televisions and blown-away washing races across the sky instead of clouds.

When the dark and dangerous chemical Smog threatens to seep back and destroy the real London, Zanna and Deeba find themselves caught up in the battle with a motley posse of UnLondoners, including a bus conductor with an airborne Routemaster, and a band of battling umbrellas. There are powerful threads of invention in this giddy flight of fancy.

Darkside (Waterstone’s Children’s Book Award winner) is an altogether deeper and more disturbing story of the quest of Jonathan Starling, a lonely, sensitive teenager, who sets out to find the source of the horrors that haunt the mind of his mentally ill father.

His search takes him to Darkside, a lurid, Dickensian place reached along the River Fleet, which flows under London. It is full of forceful, malevolent characters such as the lurid Marianne, whose perfume induces forgetfulness, and Carnegie, the honourable gangster.

Den of Thieves is the third novel in the rip-roaring saga of Cat Royal, the orphan girl who has grown up in Mr Sheridan’s Theatre Royal, Drury Lane.

This tale finds Cat homeless while the theatre is being rebuilt. The scene then shifts to revolutionary Paris, with Cat sent on an undercover expedition to send back reports from a city in turmoil.

Julia Golding’s thoroughly entertaining novels offer a lively and absorbing, if somewhat stylised, introduction to the late 18th century