The production was nine months filming and an extra year in the editing suite.
700 hopefuls appeared at an open audition for the show in Stoke-On-Trent.
The ending of the original book by Tim Pears was rewritten for the TV adaptation.
Certain scenes were not orchestrated - actors were left to play amongst themselves, with the intent to add more realism.
There were over 140 acting parts to be filled.