|Series 05, Episode 03|
|Air Date||25 September 2006|
|Previous||Gas and Oil (2)|
The Cell is the third episode of spook's fifth series which aired for the first time on 25 September 2006.
Zaf goes undercover to infiltrate an Al-Qaeda cell, who are preparing to attack London with a thermobaric weapon. Ros also tasks Zaf to try and turn one of the members, who broke up with his girlfriend after converting to Islam.
By the time the weapon arrives in England, he is able to commandeer the weapon, but Adam discovers that someone is planning to detonate the bomb remotely; armed units are able to take him down. Meanwhile, Harry and Ruth start a brief affair, which Ruth ends after learning everyone knows about it.