BEVERLY HILLS, Calif. -- "Sherlock" fans have grown familiar with the waiting game between TV seasons, but they may be encouraged that show-runner Steven Moffat says he could see it "going on for a long while."

Speaking to TV critics Saturday at a bi-annual panel, Moffat said he and co-executive producer, Mark Gatiss, are game to keep going.

"I don't think it will be us that switch it off. I imagine it'll be down to Benedict (Cumberbatch) and Martin (Freeman.) Obviously we can't do the show without them, and they've always said they're happy to carry on so long as it's good."

In fact, Moffat would embrace a more mature Sherlock and Watson.

"I'd like to see them age, not because I'm a sadist. Just because it would be interesting to see them become the more traditional age of those characters, which is in their fifties. They're much younger than the normal version."

Production on new episodes is expected to begin in the spring of 2016, but Cumberbatch and Freeman filmed a one-off episode set in the Victorian-era that has been rumoured to air this Christmas in the UK.

"We've never said it's a Christmas special," said Moffat's wife and "Sherlock" producer Sue Vertue.

"It's probably Christmas-ish," added Moffat. "We don't actually know. We're not making this up."

"I think we are working very hard on it to not frustrate the fans who know it's on BBC and want to see it," added PBS' Masterpiece Chief Rebecca Eaton.

What Moffat could say was that his leads enjoyed doing a period "Sherlock," but one actor seemed to like it more.

"By the end, Martin was ready to go back to the more acerbic version, but I think Benedict really enjoyed being Victorian Holmes. He was saying halfway through, "Let's always do this. I quite like it,'" said Moffat.

They decided to jump back in time for an episode because "We checked the books and discovered we got it wrong," joked Moffat. "We should have read them first. No, just because we can, really."

Viewers should not expect an explanation for the time jump. "We never bothered explaining what they were doing in modern London, so why bother explaining what they're doing in Victorian London, when that's where they're supposed to be?"

Moffat also commented on the British government potentially yanking public funding from the BBC.

"It staggers me that we got a government that got elected and decided the main problem with Britain is our national broadcaster... There must be something more important to do," he said.