大象传媒

A former MI5 officer has revealed how his work managed to stop an Islamist extremist from carrying out an imminent terror attack on a group of British schoolchildren.

"Tom Marcus" - whose real identity cannot be revealed - has written a book, Soldier Spy, about his time as a surveillance officer, which has been cleared by MI5.

In this exclusive interview for the programme, he also talks about his difficulty finding a new job due to the gaps in his CV.