The Maul and the Pear Tree, By PD James and TA Critchley

A maul is a kind of mallet, which was used to club a family to death (baby included) in London's East End in December 1811. The country was plunged into a frenzy of fear. Twelve nights later, an elderly couple and their maid were found bludgeoned to death. Public opinion demanded a culprit, and an Irish seaman named John Williams, who lodged at the nearby Pear Tree inn, was arrested. With the trial still ongoing, Williams was found hanged in his cell, and posthumously convicted.

PD James and the historian TA Critchley re-investigated the case for their now reissued 1971 book, drawing on court records, newspaper accounts, Thomas de Quincey's essay on the murders and other, unpublished sources. They find Williams' conviction unsafe. The evidence against him was slender for one of the massacres and non-existent for the other, and he was probably a victim of anti-Irish feeling: "a blatant example of racialism and anti-Catholic prejudice".

This is a grim but compelling picture of an uncivilised corner of Regency England, and a spate of brutal murders which, like the Jack the Ripper murders later in the century, remains unsolved.