Scottish actor Martin Compston has told how shooting the intense interview scenes in Line Of Duty can be so exhausting that his accent slips.
The actor speaks in an English accent when he is playing Detective Sergeant Steve Arnott in the BBC Two crime drama - and even keeps up Arnott's tones off-set.
He told Radio Times of shooting the interviews in the glass office: "It's a draining couple of days' filming. You do maybe 20 takes of up to 25 pages of script on the first day.
"Making series two, it was the height of the summer - it was very, very hot and the lights made things worse. People were drifting off - it was hard to keep concentrating.
"Fortunately the new boxes for series three are bigger and better ventilated. You still sweat, though, and you get so tired. Sometimes I hear my accent slipping and the Scots burr leap in."
Compston, 31, said in series one they considered shooting the scene in different takes, but Lennie James (who played DCI Tony Gates) wanted to run the full scene.
"He was right - it changes the scene completely when you do it through in one take," he said.
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