Line of Duty, BBC1

****

OH Ted, how could you? With those matinee idol looks and what we thought was your cast iron morality, why take a nation’s heart and break it so? You have let us down, fella, especially the ladies.

For the benefit of the tape we refer not to Superintendent Hastings being cleared of the suggestion that he is “H”, the head of a network of corrupt officers in league with organised crime. We never suspected him for a moment. Even when Line of Duty creator Jed Mercurio all but hung a neon sign over his head spelling out “GUILTY”.

Read more: Why Line of Duty is a national treasure

No, that is not the reason the nation’s women are giving Ted an old-fashioned look today. We refer to the moment in last night’s finale in which the head of AC-12 confessed to ogling mucky pictures. “I was looking at pornography,” Ted told his interrogator sheepishly when she accused him of destroying a laptop because it contained data confirming he was H.

Read more: Line of Duty: 12 AC-12 related questions answered - or not - in finale

Not for the first time in this special 90-minute episode, you could have heard a gnat’s sewing needle drop. “Nothing illegal, nothing extreme,” Ted rushed to add. “I just did not want it to be found.” We will talk about this later, fella; there is too much else to be getting on with, in particular asking if last night’s curtain dropper met the show’s extremely high standards.

Mercurio certainly gave loyal fans value for money, skilfully pulling together strands and characters from previous series. The addition of Anna Maxwell Martin to the mix as Chief Super Carmichael was a masterstroke. If pursed lips could kill, the body count for this series would be even higher.

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Adrian Dunbar was outstanding as Hastings, a man whose assumptions about himself as a fundamentally good man were put to the test as never before. His face on learning the truth about undercover cop John Corbett (Stephen Graham) was a picture worth a thousand words. Scotland’s Martin Compston, Essex accent flawless as ever, did not have as much to do in the finale, but when he did contribute it turned out to be vital, while DCI Kate Fleming, played by Vicky McClure, showed she has the makings of an AC-12 chief if a vacancy should arise.

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But some elements were decidedly iffy. The big reveal about H, or rather the contrived way it came about, was as close as Line of Duty has ever come to jumping the shark, of pulling a move so outrageous that it has viewers throwing their hands in the air and shouting, “Oh, come ON!” The will-there-won’t-there be a last minute flee from the scene borrowed heavily from a past episode, and some characters were rather too obviously set up to be wrong ‘uns.

Above all, there were too many things sprung on the viewer at the last minute, things they could not possibly have known, such as what Vicky and Steve discovered about Corbett’s past that had them tearing back to HQ. Agatha Christie would have taken a dim view of such brazen jiggery-pokery, but then Aggie was not writing a blockbuster police procedural in a multi-channel television age.

The ratings so far

The millions of viewers who have made Line of Duty the most watched programme of the year will forgive the odd dodgy moment in the finale because this series as a whole has been excellent. In Corbett, Mercurio created a character of real substance, one whose background brought the past woes of Northern Ireland into timely focus once more. He showed that even after so many series and twists, a great dramatist can still make you yelp with shock; and he demonstrated that there is life in this tale yet. Another series? For the benefit of the tape, 13 million viewers and counting shout “Yes”.