Line of Duty Guest cast, played by Alastair Natkiel Episode 5x01: Episode 1 (Mar 31, 2019) Episode 5x02: Episode 2 (Apr 7, 2019) Episode 5x04: Episode 4 (Apr 21, 2019) Episode 6x04: Episode 4 (Apr 11, 2021) Episode 6x05: Episode 5 (Apr 18, 2021)