“Cannot we delude the eyes/ Of a few poor household spies?” Volpone sings to Celia in Ben Jonson’s play. On the evidence of these two books, the answer is “No.” Consider the fate of John Somerville, a Warwickshire Catholic who decided, in October 1583, to assassinate Queen Elizabeth. He was foolish enough to say as much before witnesses, describing the Queen as “a serpent and a viper.” Within days he found himself being interrogated by no less a person than Sir Francis Walsingham, the head of Elizabeth’s security service. He was found hanged in prison before he could be brought to trial for treason. This may have been a prudent forestalling on his part, to avoid the drawing and quartering that followed a traitor’s hanging, or he may simply have been disposed of without fuss.

This anecdote from Stephen Alford’s The Watchers is a small but telling illustration of many themes of his book: the extraordinary efficiency of Walsingham’s espionage network, the seriousness with which the most obscure dissentient voices were taken, and the implacability of the State machine. It is also a reminder of the inextricability of religious and political allegiances in the last decades of Elizabeth’s reign. A “loyal Catholic” was a contradiction in terms. Since the queen had been excommunicated by Pope Pius V’s bull Regnans in excelsisin 1570—which, incidentally, prompts the surprising reflection that England remained technically a Catholic country for the first twelve years of her reign—her Catholic subjects had been