Jonas Armstrong is due to return as the Nottingham hero for a second series in the autumn.
Dominic Minghella, the show's executive producer, commented: "The second series is darker and bigger and Robin is tortured and bullied a bit.
"The battle is not just in Nottingham anymore, it is a battle for England."
And Foz Allan, also a producer, explained: "In the first series Robin was growing between a boy and a man. Now Jonas has beefed up quite a lot and is definitely a man."