Inspector Minahan Makes a Stand, or The Missing Girls of England, By Bridget O'Donnell. Picador, £16.99

A 13-year-old girl sold for a fiver, a bobby out for revenge, a clutch of crusading reformers, two sensation-mongering reporters and the scandalous sexual preferences of the upper classes – all are pivotal to Bridget O'Donnell's Inspector Minahan Makes a Stand. The year is 1885.

The selling of Eliza Armstrong isn't new material. Apparently trafficked as a prostitute, Eliza unknowingly played the starring role in a piece of early investigative journalism. But – misfiring spectacularly – it ended in the jailing of William Stead, editor of the Pall Mall Gazette. Exposed by a rival newspaper, Stead had "bought" the girl to show how easily it could be done, then squirreled her abroad with the help of the Salvation Army. Stead titillated the nation with his rants about London's predatory sexual mores, boosting his paper's circulation while mounting a serious campaign to get the Criminal Law Amendment Act passed, raising the age of consent from 13 to 16.

In recycling this story, O'Donnell includes Mary Jeffries, the notorious madam and trafficker whose girls and boys catered for a "late night finish" for such eminent gents as Leopold II of Belgium and "Dirty Bertie", later Edward VII. But she weaves in, too, the tribulations of the Jeremiah Minahan, an Irish police inspector demoted for not being bent enough. Minahan had put Jeffries's Chelsea brothels under surveillance and gathered sufficient intelligence to embarrass, personally, the Home Secretary, Sir William Harcourt.

Using verbatim accounts and quoting court reports, O'Donnell captures all the colour of a Victorian melodrama. Here's Minahan "nudging seven feet tall" in his helmet; there the limping, raddled former procuress Rebecca Jarrett kitting out Eliza in a doxy's outfit of purple dress and red feathered hat.

The book promises "secrets… so fearful" that Minahan "took them to his grave where they have remained – until now". The final reveal doesn't quite live up to this build-up, but it's an enjoyable romp.