Chris Eccelston's character in 'Legend' is like a "bloodhound".
The 51-year-old actor stars in the new movie based on the book 'The Profession of Violence: The Rise and Fall of the Kray Twins' by John Pearson, and plays the policeman Leonard 'Nipper' Read, who finally takes down identical twin gangsters Ronald and Reginald Kray.
Chris said: "Me and Brian (Helgeland) did have a number of conversations about what type of dog Nipper Read might be, he decided on a bloodhound. That's because a bloodhound - according to Brian - will run until it dies, will chase its prey until its heart bursts."
But the actor didn't carry out research for the part.
He said: "I think there's a load of b******s spoke about research, I think it's make believe and I felt that what Brian had written sent me a very clear message about what he wanted."
He added: "I thought of Nipper Reid as puritanical and a man who did not want the 60s to happen, who did not want the Krays to have sex and fun, he didn't want The Rolling Stones to have fun, he was the man from the previous 10 or 20 years."
Meanwhile Tom Hardy portrays both twin brothers in the film and wasn't afraid to admit he had to do his homework for part.
Tom, 37, said: "There is a plethora of research that one can do on the Krays. We had various members of their world come out and talk.
"But there's lots of photos, but mainly people's mythic tales, people's legend, which are usually asinine, that circulate usually from people that didn't know them, you get a lot of them come out.
"Then there's patterns of stories that seem to re-appear a lot, I also had loads of diaries as well and some footage from a Panorama documentary. So I did loads of research really."