 To research for his role , Armitage read novels from authors including John le Carré , Frederick Forsyth and Robert Ludlum . He tried to inspire his acting style for Lucas by Jason Bourne , a character created by Ludlum . He also lost a stone in weight in order to keep with the description that Lucas is malnourished , but also had to keep physically fit in order to perform a fight sequence during his first week of filming . Since Lucas is a fluent Russian speaker , Armitage had to learn it phonetically , which he found " pretty impossible . " He originally tried to learn it from a disc , but found it too basic and had since moved on to a language coach . 
