MI6 operative truth or fiction?

I've just been reading the blog of a former MI6 operative .... Very interesting stuff. However, I think you have to take this sort of stuff with a pinch of salt. You know in a way the chap needs to make a living, but in trying to do so is he enriching his stories?. I don't know, and sure we'll never know ... But I'm sure he signed the official secrets act for a reason!