This is the story of Farouk, an undercover operative who foiled what police said could have been "one of the deadliest terrorist attacks in UK history".

Walid Saadaoui, 38, and Amar Hussein, 52, had a “visceral dislike” of Jewish people and wanted to kill as many as they could in their Islamic State-inspired gun attack in Greater Manchester.

But the duo were brought down after an undercover operative posed as one of them to gain their trust, tracking their every move for six months before armed officers swooped in to arrest them.

Elaine Willcox takes up the story with Assistant Chief Constable Rob Potts, from Counter Terrorism Policing North West.