Centre stage is Bill Nighy’s Johnny Worricker, a long serving and suffering MI5 officer. When his boss and best friend suddenly dies, he is left to navigate what soon reveals itself to be a treacherous tangle of intrigue, winding right to the very top of the British political establishment. As the Arab spring heats into summer, this is powerfully timely state of the nation stuff, and yet a finely drawn, personal character study, attacked with detail and aplomb by Nighy, that most subtle of virtuosi.