Stephen Tompkinson has his first lead part on the big screen playing a gritty "old school" British cop in Harrigan.
In contrast to his fictional role as a charming smalltown police officer in ITV drama DCI Banks, the new film is written by ex-policeman Arthur McKenzie, based on his own experience fighting crime in Newcastle in the 1970s.
And Stephen revealed the two characters couldn't be more different as his new film alter ego is a hard-nosed maverick, determined to clean up the streets.
He said: "I think the modern policeman has to treat things very carefully. You have to be seen to dot all the 'i's and cross all the 't's because clever lawyers can get clients off on technicalities if you don't do everything absolutely by the book.
"And I think there was lot more leeway and freedom, for both police and villains to operate in. And I think there was a lot more mutual respect, by seeing the physical presence of a police officer on the street, you tended to keep your nose clean when they were around."
Stephen - who is currently starring in Monty Python musical Spamalot on the West End stage - believes the film will strike a chord, with the current cutbacks in frontline policing.
He said: "It's set in a grim time when the three-day week was on and there were a lot of power cuts, and local police stations in the city were being closed down and they were going in for bigger more centralised police stations, and the 'Bobby on the beat' was being replaced by the panda car and certain estates were turning into Lord Of The Flies.
"And Harrigan comes back and cleans up an estate pretty much single-handed. That's the sort of policeman Arthur was, he thought the presence on the street was the most important thing, and to serve and protect."