'Rich, densely plotted... If le Carré needs a successor, Williams has all the equipment for the role.' Times Literary Supplement Books of the Year'The most authentic spy novel ever written [...] an utterly fascinating account of a very dangerous time in British history when elements of the Secret State were out of control' Edward Wilson'Gripped me, not just because of its crisp writing but because of its skilful blending of history and imagination... A clever cautionary tale' The TabletLondon 1963.

The Beatles, Carnaby Street, mini skirts. But the new mood hasn't reached the drab and fearful corridors of MI5 and MI6. Many agents joined the secret service to fight the Nazis.

Now they are locked in a Cold War against the Russians. And some of them are traitors. The service has been shaken to its core by the high-profile defections of Cambridge-educated spies Burgess, MacLean and now Philby.

Appalled at such flagrant breaches of British security, the Americans are demanding a rigorous review. Harry Vaughan is brought back from Vienna to be part of it. The Chief asks him to join two investigators - Arthur Martin and Peter Wright - who are determined to clean out the stables, and the first target of their suspicions is the Deputy Director General of MI5, Graham Mitchell.

Harry slips back into a relationship with an old flame, Elsa, and joins the hunt - somewhat reluctantly. He is sceptical of the case against Mitchell and wary of the messianic fervour of the two spycatchers. But the further the investigation goes - and the deeper his commitment to Elsa becomes - the greater the sense of paranoia and distrust that spreads through the 'wilderness of mirrors' that is the secret service.

The only certainty is that no one is above suspicion. Including Harry Vaughan. ***'Every bit as cynical in tone as Mick Herron's Slough House mob' Irish Times'If a good spy novel needs anything, it's uncertainty, a hall of mirrors; and Witchfinder delivers it in spades.

Great stuff' Dominick Donald, author of Breathe'One of Britain's most accomplished thriller writers' Daily Mail'Williams is an accomplished thriller writer and this may be his best book yet. London in the 1960s, its smoky pubs, damp streets and crackle of sexual liberation is so well portrayed that reading Witchfinder is almost like time travel. Williams blends fact and fiction to make a captivating read.' Financial Times