The third series of Sherlock is hotly anticipated – with Steven Moffat and Mark Gatiss continuing to puzzle fans eager to figure out how Sherlock apparently faked his own death. But the creators, joined by Moriarty actor Andrew Scott, tell Vicky Frost three words to get fans thinking – and discuss what next for the consulting detective, the theories they enjoy, and the secret of creating such a brilliant show. Plus: what can we find out about Doctor Who anniversary celebration?