Karen Pirie writer explains how series' format was changed

However, speaking exclusively with RadioTimes.com, the show's writer Emer Kenny, who also stars as River Wilde in the series, revealed that was not always going to be the case.

She explained: "Originally ITV said to me, 'Do you want to do one book per two hours?' – but the original book was 600 pages long or something. And I was just, like, 'If I do that, it will just be plot, there will be no character, there will be no texture, there'll be no humour...' and humour is so important to me."

Kenny continued: "I've been a comedy actress for a long time and I find it really difficult to write anything that doesn't have some element of gags and jokes in it. So I said, 'I just don't think it's going to fit, I don't think it's going to work', and so I ended up pitching the way that I did it, and they were happy with it.

"I am so glad that we got that extra time. Obviously it's unusual to have a two-hour but I think it allowed all of those things that I've mentioned in each episode to expand a little bit from the usual 60 minutes."

Meanwhile, at an event attended by RadioTimes.com and other press, executive producer Simon Heath explained that at one point the series was going to be made up of one-hour episodes, but this was changed after the first script was written.

He said: "As you often approach these things, you go with the standard format and Emer’s initial pilot was for an hour, and it worked and it was greenlit. And then I got a call during the first lockdown saying that there was the opportunity to look at the show as a series of two-hour films. And I called Emer and talked her down off the ledge."

However, like Kenny, Heath was quick to state the benefits of the two-hour model, saying: "I think when we started talking about it I could see big advantages. What it does is it gives Emer the space to write the character stuff, the issue stuff, the thematic stuff, that sometimes when you boil it down to hour-long episodes, it just becomes plot, plot, plot."

Similarly to the book on which it is based, the show operates across two timelines - although in the show they are intercut, rather than being told one after the other. Heath said this wouldn't have been possible with a one-hour format.

He explained: "I don't think we could have done the two timelines across an hour. Imagine how little you could fit into 47 minutes when you're cutting between 1996 and 2021.

"It was difficult initially to get your head around that but once it was delivered it was like, 'Oh my god, this again will make it feel distinctive', because traditionally those two-hour films we know are kind of self-contained stories but this was going to be serialised. I think probably Prime Suspect would be the last time you've had serialised two-hour episodes of something."

Additional reporting by Morgan Jeffery.

Karen Pirie begins on Sunday 25th September at 8pm on ITV and ITV Hub. You can also get a 30-day free trial of ITV Hub+ on Amazon Prime Video here.

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