In the course of an apparently hopeless effort to defend a young woman on a charge of murdering her cousin, the lawyer Matthew Shardlake receives some unexpected help from Thomas Cromwell, King Henry VIII’s chief minister: a 12 day postponement on the case to allow him time to marshal a proper defence. In return Cromwell, requires Shardlake to undertake an investigation on his behalf: to locate the formula and means of making Greek Fire, the legendary incendiary weapon of the Byzantine empire. This is rumoured to have been discovered in the library of a monastery that Cromwell’s philistine policies have had vandalised in the course of the Dissolutions.

C J Sansom, the author, is both a historian and a lawyer, as well as a novelist. So this book, the second in his series about Shardlake, is rich in detail both of the political and religious controversies and the legal practices of the time. Shardlake, and so presumably Sansom himself, considers Cromwell as the lesser of evils that could befall the English state, but doesn’t skip over the atrocities the man was capable of: Shardlake’s memory of how Cromwell had a Catholic priest slow-roasted to death is a particularly chilling passage in the book.

In spite of the careful attention to historical detail Shardlake is the very model of a modern Londoner: humane and rational, his best friend, Guy, a Catholic physician and apothecary of Moorish origin, his side kick, Barak, a secular Jew. As such he is a companionable guide to the mad slaughterhouse that was Henry VIII’s London, a place more like a European Saudi Arabia, or Islamic State (DAESH), than the place we are familiar with in the 21st Century.

The result is a gripping and unusual crime novel, as Shardlake and Barak grapple with the parallel mysteries of a child murder and Greek Fire. I look forward to the rest of the series.