Sherlock: The Final Problem SPOILER FREE review ★★★★★

Calling all hard-core Sherlock fans: clasp your hands together, place them under your chin (like an otter) and pray. Pray that this isn't actually the last ever instalment of the show. Pray that this innovative and clever programme hasn't disappeared off into the night with its tale between its legs, having carelessly dumped this steaming pile of Sherlocky-flavoured nonsense onto us.

Last week, we had the best of Sherlock: a tsunami of emotional incontinence from Dr Watson and Mr Holmes; a sinister villain inspired by Jimmy Saville and a smattering of clues littered throughout the episode that, when re-watched, showed Sherlock outwitting the baddie, one trick at a time.

Unfortunately, as writers Mark Gatiss and Steven Moffat were occasionally wont to do when they wrote Dr Who, one tightly written episode was followed up with a load of cop-outs and half-baked thinking.

'The Final Problem' began promisingly enough, with a haunting scary-movie style scene designed to force Mycroft to reveal the truth about his secret sister. Then a drone appeared in 221B Baker Street giving everyone the opportunity to say some funny one-liners and jump out the window. Sherlock and Watson had some banter and Mycroft was abrasive. So far, so Sherlock.

Unfortunately, all good sense apparently jumped out the window with the boys, and it didn't survive the fall. Sherlock's sister has an inexplicable, magical control over people. Sherlock barely tries to outwit his enemy, preferring to throw a series of tantrums whilst going through the tasks laid out for him by the villain. No one has a problem believing the little girl making phone calls at 30,000 feet from an airplane in which everyone else is unconscious. And Dr Watson spots the danger before Mycroft does. What. Is. Going. On???

To its credit, the episode explores the emotional depths in both Sherlock and his sister, offering a sympathetic look at villainy. Following 'The Lying Detective', in which a beloved celebrity is exposed as a monster, it's interesting to explore the ways in which monsters can (or should) also be beloved. And, of course, the magnificent Benedict Cumberbatch and Martin Freeman are unstoppable as always. They, at least, will be missed.