'Utterly shocking. Blunt wasn't just an arch-traitor. He was a callous mass-murderer. A war criminal no less. And it's hard to say which is the greater sucker punch - Blunt's dark treachery, or the British establishment's cover up of his crimes. It is high time the truth was revealed. Blofeld's book does just that. Bravo' Damien Lewis

In a brilliant feat of literary detective work Master of Lies tells the extraordinary untold story of Anthony Blunt's life as a spy. Based on extensive research into newly released files he is revealed as not simply "the fourth man", but the most dangerous spy of the twentieth century.

During the war, as the fate of the world hung in the balance, Blunt's intelligence was being fed straight on to the desks of Hitler, Stalin and Churchill. His hand was secretly guiding our collective fate and his treason led to the deaths of tens of thousands. He casts a shadow which looms large to this day.

The official narrative is that Blunt was the least of the Cambridge spies - and yet he was the one who got away with it. While the rest drank themselves to death in dingy Moscow flats, Blunt revelled in his brilliant career as an art historian, Surveyor of the Queen's pictures and Knight of the Realm. He was protected not just by his many friendships with the great and the good, but by the brilliance with which he played the game - his was a secret too big to be told.

Master of Lies reads like the best spy fiction but it solves one of the great espionage mysteries of our times.

Piers Blofeld is a literary agent and, apart from a brief stint as a story consultant in the video games industry he has worked in publishing for the whole of his career. A regular commentator on the mysteries of the book business he has had his own column in Writing Magazine for the last five years. Born and bred in Norfolk, his surname made it all but inevitable he would nurture a fascination with supervillainy and spying. Master of Lies is his first book.