BBC1 success follows Broadchurch, Line of Duty, The Fall and Hinterland as UK matches US and Scandinavia for drama

There was little clue in Happy Valley's title. But after six weeks, millions of viewers are finding themselves anxiously counting down to the conclusion of the latest British television police drama to grab the attention of audiences and critics.

Sarah Lancashire has given what critics agree is an astonishing performance as Sgt Catherine Cawood in a show that follows a year of hit homegrown crime dramas including Broadchurch, Line of Duty, The Fall and Hinterland.

With acclaimed performances and scripts, these complex, emotional and sometimes violent series are also bringing excellent ratings for broadcasters, with Happy Valley attracting more than 6.5 million viewers, and the Broadchurch finale 2 million above that tally.

Commissioners agree British crime drama is having something of a moment. That can be attributed to two things, said Ben Stephenson, controller of drama commissioning at the BBC: "There's the growing ambition and sophistication of British drama, and also that crime drama is a fantastic way to tell stories about people and today, while having a great driving narrative."

Happy Valley, which tells of kidnapping and the effect of drugs beyond the city, is notable for the emotional, human stories its writer, Sally Wainwright, tells. Similarly, Broadchurch, ITV's multi-Bafta-winning whodunnit starring Olivia Colman and David Tennant, which arguably marked the beginning of a new wave of interest in British crime dramas, told a story of family and community.

With a second series filming, Broadchurch writer Chris Chibnall described crime drama as being "the Trojan horse" of television. "You can pick a big issue and take the audience with you … Were you to do it through a straight drama, they might be a bit more resistant," he said.

"You can use the structure of an investigation and delve into stories and themes and issues that are quite muscular and powerful, but you're taking the audience with you on that journey."

What sets these new British crime dramas apart, says Steve November, director of drama at ITV – also home to crime duo Scott & Bailey, created by Sally Wainwright – is that they are focused less on procedure, and more on exploring their characters and the impact of crime.

"Crime drama felt like it had almost reached a natural conclusion," said November, pointing to slickly formatted popular US shows such as CSI. Now, he says, there is a distinct change of pace and direction that viewers are responding to.

Crime drama also provides plenty of variety for viewers: Line of Duty deals with police corruption; Happy Valley is driven by Cawood's past as much as her policing; Hinterland, set in west Wales, has a sense of place that makes it quite distinct from other British drama.

"We're in a really great place with Happy Valley, Line of Duty, Scott & Bailey," said Chibnall. "But they're all really different. They're all in the genre, but they take a very different approach."

It is notable too that recently acclaimed shows such as The Fall, starring Gillian Anderson, and the second series of Line of Duty, written by Jed Mercurio, both of which attracted audiences of more than 4 million on BBC2, take the form of one storyline explored over a number of weeks, rather than weekly mysteries.

There has been a shift in approach, said Stephenson. "That has changed over the last five years … Telling stories over six hours rather than one can sometimes allow you to tell quite complex stories."

Chibnall and November both point to the success of Scandinavian-noir, in particular The Killing, in terms of changing the way British television executives commission crime drama. "You could go and pitch an extended drama, not just an episodic drama. The door to the commissioner's office was suddenly open," said Chibnall.

The popularity of imported crime drama was particularly helpful to Hinterland, filmed in English and Welsh, and screened with some subtitles on BBC4. A second series is currently in production.

"It really helped us because the perception was that British and American audiences didn't like subtitles," said Ed Thomas, the show's writer/director.

• Happy Valley concludes Tuesday, 9pm, BBC1

• This article was amended on 3 June 2014. An amendment was made on 2 June to clarify that Happy Valley was set in West Yorkshire, not west Wales. In fact, the reference to west Wales in the original story was being made, correctly, to the crime drama Hinterland. The original reference has been reinstated.