Line Of Duty Fans Are Only Just Realising Steve Arnott Actor Martin Compston Is Scottish

Writing on Twitter, one viewer said: "I'm probably gonna get slated for this. But I nearly fell off my chair when Martin started talking. I had no idea he was Scottish."

Another chimed in: "Wow I have never seen you in anything else except line of duty. I have no idea you were Scottish. You do a great accent!! Can't wait for tonight's final episode. Seriously hooked."

A third wrote: "Just watched last night's @wossy show..... am I the only one who didn't know @martin_compston is Scottish."

While another added: "Had no idea u were Scottish in real life! On series 2 catching up to the new series."

Others, though, were surprised by the fact that other people were surprised.

"I can't believe there are still people out there who don't realise @martin_compston is Scottish," tweeted one.

The season finale lands later tonight (2 May), with fans hopeful that we will finally get the identity of 'H'.

However, some fans have taken matters into their own hands in an effort to work out for themselves who is behind the OCG.

Katie Rogers, from Dorset, is so dedicated to the cause that she has watched each episode of the current series five times, analysing every scene.

She said: "The show is so great and interactive.

"Over the last 12 months [of lockdown] we've got more and more disconnected and not been able to see people and this has brought us back together.

"I think I speak to my family twice as much since the show started compared to before."

However, she says she was hooked as soon as she started, and just loves playing amateur detective.

"I joined it about series three and discussing theories just made me get more into the nitty gritty of it," she told the publication.

"I think when you watch another series, you have to watch it all from the very beginning again because it all ties up."