According to the judge at her trial Shell Dockley is 'evil personified'. Inside Larkhall, Shell rules the roost, getting other prisoners to do her dirty work for her. Her hands are always clean. Shell's a man-eater who has a special man inside Larkhall - Jim Fenner. Shell adores him and lives for her snatched moments with him. That is until she finds out he has another prisoner in his life ...

Debra describes her characters as "a bit of a bitch, a slapper and a psycho. She is always using her sexuality to get what she wants. Shell is definately the top dog to start with - but she is driven by jealousy and anger and hatred, and so there are a lot of people who don't like her."

But Debra doesn't see herself like that at all. "I don't think there is very much of me in Shell at all, so I've had to look around for inspiration. The ways Shell and I would react to the same situation is very different. So playing Shell, I've thought what I would do in a situation and have then done the opposite."

But Debra has certainly enjoyed the freedom that playing a baddie can bring. "It has enabled me to be very naughty - which is great fun. But Shell sometimes takes it too far and I've not enjoyed doing some of those scenes. I didn't relish having to attaack Joanne's character, Rachel, over and over again. That was hard to do."

Debra has never been in trouble with the law, but she is sure of how she would cope if she ever did find herself in prison. "I would keep my nose clean and my head down. I wouldn't take any risks that would mean I'd have my sentence extended. And I know I wouldn't want to be in there any longer than I had to be."

And now Debra knows exactly what kind of part she is looking for after playing such a nasty, violent character. "After playing a bitch for five months I'd love to play a nice girl in a period drama who falls in love and gets swept off her feet."