With time running out, AC-12 attempt to unmask ‘H’, the Fourth Man – or Woman – commanding the network of corrupt officers behind the murder of Gail Vella.

But sinister and powerful forces appear intent on orchestrating a cover-up.

(Picture: BBC)
  • Director – Jennie Darnell
  • Producer – Ken Horn
  • Writer – Jed Mercurio


  • Adrian Dunbar as Hastings
  • Amy De Bhrún as Steph
  • Andi Osho as Gail
  • Anna Maxwell Martin as Carmichael
  • Anneika Rose as Farida
  • Claire-Louise Cordwell as Leland
  • Gregory Piper as Ryan
  • Kelly Macdonald as Jo
  • Laura Elphinstone as Brandyce
  • Maria Connolly as Merchant
  • Martin Compston as Steve
  • Nigel Boyle as Buckells
  • Owen Teale as Osborne
  • Perry Fitzpatrick as Lomax
  • Peter De Jersey as Rossport
  • Rosa Escoda as Amanda
  • Shalom Brune-Franklin as Chloë
  • Tommy Jessop as Terry
  • Vicky McClure as Kate

The series finale of Line of Duty airs on BBC One at 9pm