Oscar winner Cillian Murphy has returned to the gritty world of “Peaky Blinders” with a new film set during World War Two.

The Irish actor reprises the role of Birmingham gangster Thomas “Tommy” Shelby, leader of the Peaky Blinders gang, now ageing and stepping out of retirement to foil a Nazi conspiracy in the central English city of Birmingham.

“I was always up for it, the idea… We were developing the script for years… just trying to get it right, see if we could justify its existence because it’s a different beast, like a two-hour story as opposed to a six-hour story,” Murphy told Reuters, referring to the “Peaky Blinders” series.

The series first aired in 2013 and went on for six seasons, each comprising six episodes. The first season was set in 1919.

The film, titled “Peaky Blinders: The Immortal Man”, introduces new cast members including actors Rebecca Ferguson, Tim Roth and Barry Keoghan who plays Tommy’s illegitimate son, Duke Shelby.

Their relationship provides the emotional heart of the story.

“When we got the story… clicking, it became just about family, about father and son,” Murphy said.

“The violence is the backdrop… you look at ‘The Sopranos’… it’s the moments in the kitchen. It’s all family,” Keoghan added.

The Netflix film was written by the series creator Steven Knight.

“I always wanted from the end of series one to end this part of the story with a film, and also to have that film set in the Second World War,” he said. “It was always an intention to finish it in this way.”

Knight, who is also penning the upcoming James Bond movie, opens “The Immortal Man” by recreating the 1940 bombing of the Birmingham Small Arms (BSA) factory, where his mother worked.

“My mum was working at the BSA factory at the time, putting explosive into artillery shells, but she wasn’t on shift that night… she survived,” he said.

“I’ve always wanted the Peaky thing to be rooted in those sorts of personal stories.”

“Peaky Blinders: The Immortal Man” begins streaming on Netflix on March 20.