BULLETPROOF's Noel Clarke revealed a shocking story of an undercover case where an agent slept with a criminal and even bore his children before sending him to prison.
The agent was in so deep that she started a family with the crime boss, but that didn't stop her from seeing through the task at hand and getting him sent down.
Most of the research for the show, including working with real police officers, came prior to the first series. Noel, 44, along with his co-star Ashley Walters, 37, took lessons in how to use firearms and also learnt more about going undercover.
Clarke explained: "They get deep. There's stories of people having babies, deep undercover stuff." Walters added: "[There was] this woman that had gone that deep undercover.
Read more on thesun.co.uk