Season four of espionage drama quotMI5quot finds the team reeling from the loss of Danny David Oyelowo, but thrown back into action when a bomb detonates near his funeral Zafar Younis Raza Jaffrey and Juliet Shaw Anna Chancellor are introduced to the show, in a story involving a potentially devastating terrorist attack in the capital Later in the season Lyndsay Duncan guest stars as a former MI5 officer with a deadly grudge, one which threatens the lives of everyone back at The Grid
