Speaking to RadioTimes.com and other press, McGovern said he had Bean and Graham "uppermost" in his thoughts when he wrote their characters: Mark (Bean), a soft-spoken inmate, and Eric (Graham), a principled prison guard.
"I did. I had those two [actors] uppermost in my thoughts all the way through," he said. "Yeah, absolutely. Because I just think that they've got faces you’d die for, you know? Full of life; full of compassion and humanity. I think if you're going to write about a prison, that's the kind of thing you need, isn't it? Compassion, humanity, experience all in the lines of those faces."
Graham responded, "It's such an honour for me to even hear that Jimmy's considering me while he's writing the character. For me, that’s something that’s beyond my wildest dreams."
On working with Graham and McGovern again, Bean previously said, "Getting to be involved in a Jimmy McGovern drama again is a real privilege and it will be great to be reunited with Stephen. Mark Cobden is another of Jimmy’s complex and superbly written characters and I am looking forward to bringing him to life on screen."