The decision of the filmmakers to essentially pick up where the TV show left off instead of rebooting with completely new characters, leaves this film with a difficult task and unfortunately anyone who has not seen the show will no doubt feel somewhat underwhelmed by it all. Much of the character development and some of the twists rely on audience awareness of characters and elements from the show to have their greatest impact and without that, it is likely to leave some viewers cold. That being said, it is easy to understand why the filmmakers stuck with this model as it allows them to ensure the series' greatest asset, Peter Firth, is front and centre throughout and for fans of the show (like myself) it is great to see him again, not least because he is the best thing about the film. It also does what Spooks often did so well, providing surprises in its willingness to show the murky choices Firth's character has to make - the tagline "The Greater Good" could be one that is equally applied to the show as a whole. Disappointingly however, whereas the TV show left us with a satisfactory sense of closure, the filmmakers are hoping for future instalments, and make the mistake of leaving Firth's character and the story, open-ended.