Jack Could Come Back

Since his initial appearance in Series 1 and return in Series 3, the return of Captain Jack Harkness has been the subject of much debate. Steven Moffat has given some insight into the subject:

"When we've got a good story, we'll do it," he says. "You can't just bring somebody back and say 'that's a story'. I'll be thinking, 'you know what this needs? We need to bring Jack back for it.'"

 He also told how he had plans to bring back for A Good Man Goes to War, but was unable due to filming for Torchwood.

 “I’d have [brought back  Jack] for ‘A Good Man Goes To War,’ because it’d be obvious for him to call upon Jack in those circumstances,” says Moffat. “But John was busy doing Miracle Day.” 

And on the Doctor ever coming to Torchwood:

“The Doctor could never go to Torchwood,” Moffat says. “Russell [T Davies] and I both agree on that. Doctor Who has a tremendous relationship with children in Britain. They’d want to watch Torchwood then, and it’s not really a children’s show.”

Captain Jack for 50th Anniversary?

John Barrowman, the actor portraying Captain Jack Harkness wants to see his character return to Doctor Who for the shows 50th anniversary in 2013.

He explained at the Torchwood: Miracle Day Comic-Con panel: “Torchwood and Captain Jack were born from the mothership,” he said. “I would love to do it… I think it would be disappointing for the 50th anniversary for a character like Captain Jack not to make some kind of appearance for the 50th anniversary show.”
Adding that there it would be interesting to see how the 11th Doctor gelled with Jack: “I think there would be a different kind of dynamic there with Jack and the [11th] Doctor.”

In response, Matt Smith said, “It’s the 50th year coming up, so maybe…”