The fourth series of the British police procedural television programme Line of Duty was broadcast on BBC One between 26 March and 30 April 2017.

They are also aided by PC Maneet Bindra (Maya Sondhi) as well as DC Jamie Desford (Royce Pierreson), who is briefly assigned to the team.

Supporting characters include ACC Derek Hilton (Paul Higgins) and DS Sam Railston (Aiysha Hart).

Line of Duty was created by Jed Mercurio, who executive produces the series alongside Simon Heath and Stephen Wright.

[7] Mercurio wrote the series and executive produced it alongside Simon Heath for World Productions and Stephen Wright for Northern Ireland Screen.

[9] Thandie Newton joined the series as Detective Chief Inspector Roz Huntley, the latest police officer to be investigated by AC-12.

[11] Aiysha Hart, Maya Sondhi, Lee Ingleby, Patrick Baladi, Royce Pierreson, and Tony Pitts also appear.

[36] Den of Geek's Louisa Mellor commended the amount of action in the series-opening episode stating that there was a "car accident, an abduction, an escape attempt, a police chase, a firebomb explosion and a rescue" all before the opening credits.

"[38] Rachel Cooke of The New Statesman wrote that the second episode was "as well built as any in the last series" but feared that Line of Duty would become a "pastiche of itself" as Mercurio attempted to top himself.