For fans of a good old-fashioned spy story, there is one name that stands head and shoulders above the crowd: John Le Carré. He is a master of the genre and with a new version of his classic tale Tinker, Tailor, Soldier, Spy hitting the big screen soon, it's likely that there will be a renewed interest in our security services.
His twisting story of espionage, intrigue and betrayal has been filmed before by the BBC, with Sir Alec Guinness as the protagonist George Smiley. This time round it's Gary Oldman donning the horn-rimmed specs and seeking out a mole in “The Circus”, and the big budget movie is set to lift the lid on a secretive world once more, albeit a fictional one.
But things have changed since Le Carré first penned his novel. Now the Security Service, or MI5, lift their own lids by publishing their history online.
It's safe to assume that there's quite bit left out at www.mi5.gov.uk/output/history, but it's a fascinating read nonetheless.
It remains to be seen if Mr. Oldman can bring George Smiley back from a bygone era, but reading though this, we hope that this is one reboot that does history, as well as it's original source material justice.
Bone up on a potted history of spooks and judge whether they’ve got it right when the film is released.
If you have a website that you want to tell us about email us via the feedback form.