Actor/writer Mark Gatiss (The Unquiet Dead, The Crimson Horror, et al) was a guest on After Who Live last night, a special live show broadcast on BBC America after Doctor Who, Deep Breath aired.
Upon the mentioning of the “two universes” of Doctor Who and Sherlock (which Gatiss stars, writes and produces), Mark stated, “which are never going to meet!” Host Chris Hardwick pushed further, asking “Never? They can’t?” to be told “No, correct.”
Current Who showrunner Steven Moffat recently said that he would be in favour of a crossover, but was being held back by the “killjoys” in his Sherlock team.
Moffat is being held back by the fact he's established that Vastra is Sherlock.
Maybe if the BBC created a 'Doctor Who/The Avengers' crossover on behalf of Disney and BBC Cyrmu Wales.
Agree with Gatiss – something I thought I'd never say, as I think his story lines for DW are pretty poor. But if they couldn't manage a DW/Blakes 7 crossover back in the classic era, then a Sherlock crossover has to be pure no-no, especially considering the quality gap.
Not only would their themes clash hideously, in the Doctor Who universe Sherlock Holmes is a fictional character in literature written by Sir Arthur Conan Doyle. In Sherlock, those stories don't exist.
Thank god for that.