Steve Arnott uncovered as H – The Line of Duty clue you missed

As corrupt officer Matthew ‘Dot’ Cotton (Craig Parkinson) lay dying, he tapped his left hand out four times, which in morse code represents the letter H.

For years, AC-12 have suspected H was the letter of a first name or surname, such as Hastings, Huntley or Hilton.

It was not until the end of series five it was uncovered there are, or potentially were, four people working as ‘H’ and so far, only three have been caught – Dot Cottan, Gill Biggeloe (Polly Walker), and Derek Hilton (Paul Higgins).

Now the loveable DS Steve Arnott has come under suspicion as being H due to events in season six, episode one.