10 Ways Your Favourite TV Shows Will Probably End

5. A Parting Of Ways - Sherlock

There's not a major narrative reason for Sherlock to end soon, more a logistical one. Benedict Cumberbatch and Martin Freeman are well-established stars now, each with an increasingly packed schedule, and it already takes an age to make just three episodes of Sherlock.

While they've spoken before about just revisiting it as and when they can, that's not really the best treatment for the show, those involved, or its fans. There's no guarantee if and when they can return, while Steven Moffat and Mark Gatiss are likely to move on to pastures new as well. And, of course, the show has already lost some supports after a divisive third season and a mess of a special.

So perhaps, with Series 4, there's a way to have their cake and eat it. There have already been signs that John and Sherlock are growing apart - he is having a family, and that will need to take precedent (unless Mary really is a bad guy, and/or those predictions about her losing the baby come true).

Cumberbatch himself has said that S4 could be the last, and while not confirmation of anything, it does show the end is being thought about. I think what we'll see is John and Sherlock parting ways, finding other things to devote their time to and no longer working together. But the door to 221B Baker Street will be left open.