You know something’s up when MI6 moves its head office to Croydon

Alan Judd’s spy novels occupy a class of their own in the murky world of espionage fiction, partly because they blend two elements of the genre that are rarely seen together. First, they are grounded in a wholly plausible version of the intelligence community, where decisions evolve in Whitehall committee rooms and the wiles of politicians and bureaucrats are just as important as the machinations of moles. Secondly, their central characters often recall an older tradition of gentlemen patriots that goes back to John Buchan’s Richard Hannay. The combination shouldn’t work but in Judd’s novels it does.

These elements meet in the character of Charles Thoroughgood, who has already appeared in three earlier books, first as a soldier and later as an MI6 officer. He knows how to nudge a committee into doing what he wants and how to bargain his way towards the truth. But he’s also a cultured man who guards most of his hinterland, even from the reader.