Ros and Harry agree to the meet Muhammed Khordad, a high-ranking member of al-Qaeda, when he tips them off about a planned terrorist attack in London at 3pm that afternoon. Khordad offers to reveal the location of the bomb in exchange for a public pardoning of two al-Qaeda prisoners.

After considerable persuasion, the Home Secretary makes a statement but it is not enough to persuade Khordad, leaving the team to launch a desperate mission to find him and force the bomb location details out of him.

Meanwhile, the Russians test Lucas’s loyalty by ordering him to make sure the bomb goes off. The team has a tough decision to make: either they defuse the bomb, blowing Lucas’s cover or they let the bomb go off – maintaining Lucas’s double agent status.

In the midst of the drama, Harry receives a call from his old mentor, Bernard Qualtrough, who names the mole within MI5 responsible for passing on top secret information about operation Sugarhorse to the Russians. Harry is shattered when he realises one of his team members is a traitor – but who could it be?