SOLVED. Secret double agent- based on true story [s]

[Ruth]

Please help me find this book! I heard a snippet on the radio in autumn 2013 about this new spy thriller. It revolves around a true story and involves British secret agents. Two men were close through training and throughout their entire career but then (after a couple of decades or so?) one discovers the other is a secret double agent for Russia (?). The book explores their relationship and the eventual uncovering of the truth. No idea about title but I remember it sounded fascinating and I'd love to take it on holiday when I actually have time to dive into a good book - please help me find it!

[Ruth]

Has anyone got any ideas? Or need any more information?

[Kris]

A Spy Among Friends: Kim Philby and the Great Betrayal by Ben Macintyre?

Btw, this book is coming out in September 2014 -
Kim Philby: The Unknown Story of the KGB's Master Spy by Tim Milne.

[Lobstergirl, au gratin]

Ruth are you saying this is fiction, although based on real people and events? Any idea if the names were changed to fictional names?

[Ruth]

A spy among friends! thats it, thank you so much!

[Kris]

Glad we could help. It looks like an interesting read. I've just added it to my TBR pile. Thanks. :)