Line of Duty star Martin Compston has hinted the sixth series of BBC hit Line Of Duty could be the last. 

Compston, who plays DI Steve Arnott in the popular show, reveled this Sunday's episode could be the last but described the end of series six as the "perfect ending" if that does turn out to be the case.  

The penultimate episode of the police procedural, created by Jed Mercurio, earned an average of 11 million viewers and 51.7% of the audience share, according to the broadcaster.

The sixth series of the BBC One show, starring Compston as DI Steve Arnott alongside Vicky McClure, Adrian Dunbar and Kelly Macdonald, will come to an end this weekend (2 May). A seventh series has not yet been announced.

Line Of Duty returned to screens in March with 9.6 million viewers, up on the last series’ finale, which earned 9.07 million.

Mercurio, whose credits also include Bodyguard and Bodies, said: “Thanks so much to everyone watching #LineofDuty6. The whole production team is thrilled and flattered by the amazing response.”

The final episode will see the search for “H” – the corrupt officer responsible for the mass conspiracy – come to an end. A trailer released on Monday (26 April) offered fans a first glimpse of the series finale.

“All these suspicious deaths were orchestrated by one officer in particular – H, the fourth man,” says Superintendent Ted Hastings. The AC-12 team are seen in a shootout before viewers are told: “Every investigation has led to this.”

What did Compston say?

A seventh series has not yet been announced, with Compston telling the Shrine of Duty podcast “we won't do one just for the sake of doing it.”

"Jed [Mercurio, series creator] always takes time after a series, like a couple of months. There's a lot of stuff above my pay grade like analytics and audience scores. He takes the emotion out of it and looks at all that."

Compston added that another series will only be written if “there's a story to be told”, and said the team behind Line of Duty “don't want to overdo it.”

"Ten years in you start to think of legacy, and if [the final episode] goes down that well it might be the perfect ending."

What can we expect from the final episode?

Compston’s comments come after Line Of Duty secured its most-watched episode on Sunday night.

The penultimate episode of the police procedural earned an average of 11 million viewers and 51.7 per cent of the audience share, according to the broadcaster.

The new series has seen anti-corruption unit AC-12 take on a new case, but Detective Inspector Kate Fleming (McClure) is no longer on the squad and is working on a murder investigation with a different department, which has come under suspicion from AC-12.

Sunday’s episode saw Acting Detective Superintendent Joanne Davidson (Macdonald), boss of the suspected department, unmasked by AC-12 and secrets about her family background revealed.

There will no doubt be more surprises in store as we reach the series finale, and of course, the makers are giving little away.

What we do know is that that with time running out, AC-12 are trying to unmask “H”, the fourth man (or woman) running the network of corrupt officers behind the murder of Gail Vella.

However, as you’d expect, powerful forces would rather the truth did not come out.