Line Of Duty creator Jed Mercurio has shared research he says indicates the show’s series finale was less divisive among viewers than generally thought.

Sunday night’s episode of the BBC One series saw DSU Ian Buckells, played by Nigel Boyle, unmasked as the mysterious H, the corrupt police officer at the top of a criminal conspiracy.

However, fans and critics were split over the reveal with some saying they felt let down and others praising the decision to avoid a more dramatic conclusion.

Writing on Twitter, Mercurio said research based on randomly polled viewers rather than online aggregation sites suggested a “far less extreme picture”.

He said the decision to opt for a “down” ending to the storyline had in fact alienated less viewers than social media suggested.

In a chain of tweets, he wrote: “No one disputes the Line Of Duty finale divided social media opinion but the audience research so far shows a far less extreme picture.

“We knew a ‘down’ ending would rate less favourably with some viewers, however all seven episodes varied by under 10% on average viewer score.

Line of Duty
Vicky McClure as DI Kate Fleming and Martn Compston as DI Steve Arnott in Line Of Duty (Steffan Hill/BBC/PA)

“The research determines the episode ratings based on randomly polling viewers, rather than sites like IMDb where scores can be skewed by users strongly motivated to register their immediate anger/adulation.

“1000 random viewers submitted scores from 1-10 which have been used to calculate the Appreciation Index (AI) as a score out of 100. The AI for the ‘down’ finale was only seven points below the next lowest in Season Six (Ep 1).

“These figures won’t stop the debate, of course, nor should they – that’s still all part of the experience of shared TV viewing. Thanks again for watching.”

The much-anticipated finale was watched by an average of 12.8 million people, with a 56.2% share in overnight viewing figures, making it the most watched episode of a drama in 20 years, the BBC said.

Martin Compston, who plays Steve Arnott, revealed that he, Adrian Dunbar (Ted Hastings), Vicky McClure (Kate Fleming) and Mercurio had agreed to get “AC12million” tattoos if the show hit the milestone – in reference to the show’s crime-busting AC-12 unit.