I usually love John Le Carre's books, but I didn't think much of Our Kind of Traitor at all. In fact it left me with almost no memory of the story except a vague outline, which was very handy when it came to watching the film. I enjoyed the screen version much more. The adaptation is good, the action was paced far better than the novel, and the acting was excellent. Stellan Skarsgaad was wonderful as Dima - he managed, I thought, to make the character sympathetic without ever losing his menace. Damian Lewis was also very good. I don't especially care for Ewan MacGregor, but I thought he did well in this. I had last seen Khalid Abdalla, who played Luke, in the role of an Islamic terrorist in 'Spooks', and I think Susanne White made an excellent choice of having him play an MI-6 officer; while I know nothing about who staffs what in Vauxhall Cross, I would imagine it's much more multi-ethnic than it used to be. Lastly, the little cameo by John Le Carre himself was a nice touch.
As to how close to the reality the story line is ... I suspect much more so than many people might like to think!
As to how close to the reality the story line is ... I suspect much more so than many people might like to think!