The filmmaker behind dark BBC Two drama The North Water has revealed which part of the book he couldn't film in an exclusive interview with

The period drama starring Colin Farrell and Jack O'Connell premiered last night, telling the fictional story of a whaling vessel in the 1800s that is hit by calamity while on an expedition near the North Pole.

Director Andrew Haigh also penned the script to the series, taking on the challenge of adapting Ian McGuire's acclaimed novel, but has revealed that there was one part that could never have made it into the show.

Avid readers may remember a section involving the crew of The Volunteer capturing a baby polar bear, but this part of the story was scrapped due to budget constraints.

"There's stuff from the book that I would like to have been able to have filmed that we couldn't do," Haigh revealed. "For example, in the book they capture a baby polar bear that becomes their pet on the ship for a while that they keep in a cage.

"But let's face it trying to film a baby polar bear is not going to be possible and the visual effects budget would be gigantic so we had to remove that from the story."

If you thought that the addition of an adorable pet would make life slightly better for the unfortunate crew of The Volunteer, think again, as they ultimately try to shoot the animal towards the end of the novel.

Perhaps then, it was the right call to get rid of this scene, as the tone of the show is bleak enough already, with our The North Water review declaring it not for the faint-hearted.

Haigh added that some scenes were cut to keep each episode within the typical 58 minute runtime for a BBC drama, but that everything important was able to make it into the final edit.

The writer-director took his entire cast and crew to the Arctic to shoot the expedition scenes, but admitted that the venture was at times "terrifying" (for more on that, check out our The North Water location guide).

Additional reporting by Jo Berry.

The North Water continues on BBC Two at 9:30pm on Friday 17th September. Check out more of our Drama coverage or visit our TV Guide to see what's on tonight.