Wednesday 5 January is a black day in the police calendar of dockland Canton and its Art Deco resort of Ocean Beach. It dawns in freezing mist and icy roads. It ends with a vanload of drugs hijacked, two policemen dead, and gunfire on the motorway. DCI Sam Hoskins and his sergeant, Jack Chance, are meanwhile embroiled in a fruitless investigation of Billy Catte, seaside arcade proprietor and club-owner.

In a political storm that pits zealous social workers against municipal gangsters, as well as police against revenge and kidnap, Hoskins holds the tenuous thread on which several lives depend …