During a recent Q & A in Brazil, SHERLOCK actor/producer Mark Gatiss confirmed fans fears. It looks like the show will not return with a new season until sometime in 2016.
Gatiss says there are a few things causing issues for the new season:
Writing three films is quite a lot of work and then getting everyone together… [it’s] increasingly difficult to get everyone’s diaries to align, so we couldn’t really do more than three every couple of years I’m afraid.
He also talked about how the series came to take on film length episodes:
We ended up doing 90 minute episodes by accident. We made a 60 minute pilot and that was going to be the format of the series. We were going to have six, hour-long episodes.
I think if we’d done that everything would be very different. We would do one where it was mostly Dr Watson, or Mrs Hudson investigates or something like that.
No word yet on if this statement nullifies the possible one-off special Martin Freeman hinted at recently.