The espionage novel is always changing form. We have had the public school adventurer like Bulldog Drummond or Richard Hannay, the glamourous agent James Bond, the working class anti-hero Harry Palmer created by Len Deighton and then John Le Carre.
Though I cannot find any evidence of this I suspect Herron did work for M16. He made his name as writer of criminal fiction and now with his espionage novels.
His anti-hero is Jackson Lamb, an unattractive figure who farts a lot and runs Slough House, a rest home for agents who have totally messed up. One such is River Cartwright who fails to deal with a Jihadist who blows himself up on the Tube. It’s possible he has been set up by MI6 and the main plot thread is Jackson Lamb’s Slough House versus the actual operational MI6 nerve centre in Regents Park.
The plot thread becomes less and less credible, for example Lamb delivers a bomb to the Regents park M16 headquarters. The novel has been acclaimed by the Telegraph as one of the twenty best espionage novels of all time. It was initially recommended by Harriet Gilbert in the book programme A Good Read and a bibliophile friend of mine who reads outside the box.
I found it a page-turner but somehow unsatisfying and I must confess reviewing it a month after I read it my recollection is poor.