Have to agree with the negative reviews.
This and the author's "Dirty War" start with the ludicrous claim that the author has daringly exposed what was actually fairly well-known British colonial counterinsurgency doctrine and how this led to all sorts of dirty tricks. There are much, much better accounts of this area, including Peter Taylor's "Brits" and the excellent "The Irish War" by Tony Gerraghty. These show, without the shallow "look what I found!" sensationalism, how the Security Force's covert tactics really evolved (stumbling fairly regularly)- from the amateurish but for a time effective Four Square Laundry to the sophisticated tactics described in "the Operators" by James Rennie, which finally succeeded in really closing down on the terrorists and helped convince them they had reached the end of that long and bloody road.
There's really nothing much secret about counterinsurgency doctrine, British or otherwise, tho states tend to struggle to re-invent and apply it to successive conflicts, as in Vietnam, NI, Iraq and Afghanistan.
Even if you started off believing all you ever heard about "British-Loyalist collusion", this author doesn't do a very good or convincing job, technically. His affectations of insight and expertise ring very hollow. Instead, the book reads more like a hack reporter trying to string together a lot of tabloid journalism with some rather weak efforts to claim some sort of "shock, horror" exposé.
Not recommended.