The police drama Line of Duty, the BBC’s most-watched show since modern records began, finally came to an end last Sunday. It had teased viewers, who numbered 12.8 million by its final episode, as to who the identity of the criminal mastermind “H” would be, leading to all manner of wild speculations and social media arguments.

The final episode petered out into a glum anti-climax

The drama’s creator Jed Mercurio fanned the flames by appearing to introduce the actor James Nesbitt as a mysterious and hitherto unknown detective, Marcus Thurwell, only for Thurwell to be killed off before ever appearing on screen. Yet it seemed to make sense that the shadowy figure who had appeared to orchestrated developments since the drama began must be a Machiavellian figure of enormous sophistication. Who could he, or she, be?

The ultimate revelation that H was the plodding and vaguely hapless Detective Superintendent Ian Buckells, and that his motivation was little more than financial, came as a surprise to most viewers, and the episode petered out into a glum anti-climax. Ted Hastings, the morally upstanding head of the anti-corruption department AC-12, was forced out into early retirement, and budget cuts meant that his conniving replacement, Detective Chief Superintendent Patricia Carmichael, inherited a much-diminished organisation.

As conclusions go, it was determinedly downbeat and disappointed viewers who had expected the pyrotechnics and edge-of-seat action of previous seasons. Although there were some who praised Mercurio for upending expectations, many might have agreed with Rachel Cooke, who wrote in the New Statesman that: “Line of Duty was, for a while, the greatest cop show ever made — and then, suddenly, it wasn’t any more. Like I say, whimpers all round. Especially from me.”

However, it seems increasingly likely that, whether or not there is another series — and the open-ended conclusion certainly did not rule out the possibility of at least a one-off special to tie up any dangling threads — the concluding season will be remembered for being one of the most overtly political dramas ever aimed at a mass audience.

Mercurio, who has made no secret on social media of his antipathy to our current government and its workings, gave the character of Hastings numerous set-piece rants in which he vented to various shadowy high-up figures within the police force about the various failings of competence and decency that the organisation now faces. As Hastings stated, “When did we stop caring about honesty and integrity?”

The revelation of the feckless and plodding Buckells as H may have been a disappointment to many who expected a more flamboyant criminal mastermind to be brought in as a final guest star, but it is of a piece with Mercurio’s increasingly didactic intentions with his show. Hastings rails against “a bare-faced liar promoted to our highest office”, and it does not take the minds of AC-12’s finest to see parallels between our current prime minister and the caustic dismissal of Buckells as a man “failing upwards”.

As in the world of AC-12, blatant displays of unethical behaviour are not punished, but rewarded

As I write, it seems all but inevitable that the Conservatives are going to win the Hartlepool by-election by an enormous majority, turning a seat that has been solidly Labour since its foundation into a Tory stronghold, as with so many other Red Wall constituencies. This is not wholly unexpected given the success of the vaccine rollout, which has provided the government with a boost, but it comes at a time when Boris Johnson has been dogged by allegations of mendacity and corruption relating to the refurbishment of his flat at 10 Downing Street. It was little surprise that Keir Starmer namedropped Line of Duty in a recent PMQs in which he attacked the government for “dodgy contracts, privileged access and jobs for mates”, and quipped: “The more I listen to the Prime Minister, the more I think that Ted Hastings and AC-12 are needed to get to the bottom of this one.”

Yet for all Starmer’s apposite cultural references, it looks as if Boris Johnson and the Conservatives will have the last laugh this week. If so, this will indicate that, as in the world of AC-12, blatant displays of unethical behaviour are not punished, but rewarded. And the reason for this is that the narrative being spun by those in power is a more appealing and interesting one than the dourer, greyer account that those who oppose them can provide.

Much is made in Line of Duty of how grim and depressing the domestic circumstances of the members of AC-12 are. The protagonists are all single or divorced, have subsumed their personal lives to their jobs and all live in horrible, cheap-looking flats or bedsits. This is in stark contrast to the more luxurious lifestyles enjoyed by the corrupt denizens of the universe, indicating that crime doesn’t just pay, but that it can offer a considerably more lavish standard of home décor than John Lewis wallpaper ever could.

Traditionally, the reason why we have been drawn to villainous and amoral characters is because they are wittier and more entertaining than the often rather plodding and unimaginative heroes; dull would he be of heart who could watch Robin Hood: Prince of Thieves and side with Kevin Costner’s stolid Robin over Alan Rickman’s dastardly and charismatic Sheriff of Nottingham.

We may well agree with Jed Mercurio that integrity in public office is a bygone concept

And so it has proved in real life. We extol the entertaining shenanigans of our PM — a “messy bitch” in the arresting description of the Times’ Janice Turner — because he is funnier and more irreverent than those who seek to expose him. As a nation, we are drawn to a message of fun, gaiety and laughter, expressed by the Cavaliers, and repulsed by sermons of duty and belt-tightening, delivered by Roundheads. Even if the message itself ends up being superficial and glib, to say nothing of false, we prefer hearing it.

So it is that, as Line of Duty concludes, we may well agree with Jed Mercurio that integrity and honourability in public office might be bygone concepts now. The election of Donald Trump seemed to confirm that in 2016. Yet we do not want to be betrayed by the stolid, characterless likes of Buckells. Instead, if we are going to be taken for a ride, we want a Mr Toad at the wheel. And, judging by current events, it will take rather more than Ted Hastings and AC-12 — or the pointed commentary of their creator — to derail this particular vehicle.