London, Dec 20 (IANS): Recreating a US prison in the UK for "The Informer" was one of the biggest challenges for the makers, says producer Basil Iwanyk.

The British crime thriller revolves around Peter Koslow (played by Joel Kinnaman), a former special operations soldier working as an informant for the FBI to help dismantle the Polish mafia's drug trade in New York.

But when the FBI's operation goes wrong, resulting in the death of an undercover NYPD cop, Pete is coerced into returning to Bale Hill, the prison where he previously served time for manslaughter, to take down the cartel from the inside.

The film was entirely shot in the UK, and most of the portions are shot in a prison setting.

"The prison was a huge thing. How do you find a prison in the UK that feels applicable to a prison in New York? And then, when we're in New York, how do you find a prison that somehow matches the one we have in the UK," said Iwanyk.

Another big challenge was finding the right faces along with the accents in and around London, that one would find in a New York prison.

"Populating a prison two hours outside of London and being able to find the faces that you would find in a New York prison was probably the greatest challenge," said producer Erica Lee.

"We modelled it loosely after Sing-Sing, and if you know Sing-Sing (Correctional Facility), it's Puerto Ricans and Dominicans. That, for me, was the hardest part, the faces and the accents, alongside the production value."

"Being the only American on set, it's the thing I'm most proud of on this film, pushing extras casting, pushing our ADs, pushing everyone to find those faces, because it wasn't easy. Then really listening to the accents to make sure they felt authentic. Even the way the actors moves, played basketball, the physicality, a lot of time and effort went into planning all of that, to make it ring true," she added.

"The Informer", brought to India by PVR Pictures, will hit the screens in the country on January 3, 2020.