Sod the law of diminishing returns, A Scandal in Belgravia proves that the more Sherlock we’re given, the better it gets. The first of three new ninety minute stories, tonight’s episode was a show of staggering and justifiable confidence from the show’s creators – Steven Moffat and Mark Gatiss – a poised concoction of sauciness, comedy, brains and pathos wrapped up in a spectacularly good coat. The ringtone interruption was such a cheeky way out of Holmes and Watson’s predicament it must have had Steven Moffat giggling like a schoolgirl at the keyboard over his own audacity. He won’t have been the only one laughing. Dialling the tone of that climactic swimming pool scene from high tension to camp hilarity in just seconds is evidence of just how agile a show Sherlock is.  While we’re on the subject of agility, Andrew Scott’s switch from chilling to flustered and back to psycho in a few lines should do plenty to allay the fears of anyone unconvinced by his appearance at the end of the last series. Scott’s a fine and exciting choice for Moriarty, though he’s eclipsed in this opening episode by another recent addition to the cast, Lara Pulver as the woman: Irene Adler. Pulver’s turn as Adler ups the show’s raunch quota and opens the door to some essential questions about Sherlock. Underneath the coat, the deduction, and the cheekbones, is Sherlock a sexual animal? Is that extraordinary brain always the organ he thinks with? Is he capable of love? Before we come to all that, A Scandal in Belgravia served up not a small amount of action. For a programme largely made up of people talking, tonight’s episode packed in rogue CIA agents, head-butts, fights in alleyways, a lovely bit of defenestration, and lots of guns.  The phone proves to be a source of some consternation to Sherlock, tasked with unlocking its code while unlocking the secrets of its inscrutable owner, Ms Adler. His final deduction is as great an a-ha! moment as there’s been in the series, and just one of many really pleasurable parts of the episode. The high tension slo-mo scene of Sherlock appraising the harm meted out to Mrs Hudson [the delightful Una Stubbs] was a real joy, paving the way for a culminating line which made the audience at the episode premiere whoop: “Mrs Hudson leave Baker Street? England would fall.” Great lines were in steady supply all round, from personal favourite “Do you ever wonder if there’s something wrong with us?” from the Holmes boys, to Adler’s “brainy is the new sexy”, to Sherlock clearing his apartment of unwanted visitors to remedy there being “too much stupid in the room”. Moffat’s turned in excellent work on episode one, and next week sees Gatiss return to scripting duties for the pair’s take on The Hound of the Baskervilles. A quick word, then, on the particular genius of Moffat and Gatiss’ Sherlock. Their update strikes a difficult-to-achieve balance between delightful irreverence towards the source material whilst soaking every gag, pun and story in Conan Doyle’s words.  Sherlock’s humanity – or lack of it – has been at the fore throughout Moffat and Gatiss’ tenure as interpreters of Conan Doyle’s character. In The Great Game, Sherlock’s extreme pragmatism over the deaths of victims left Watson bewildered [a facial expression Martin Freeman should trademark]. His melancholic reaction to the apparent death of Adler in this episode then, was even more baffling to the human beings – Watson, Mrs Hudson, the wonderfully pathetic Molly – who quiz over his behaviour and aim to protect him. Moffat and Gatiss haven’t humanised Sherlock, but they pose questions about his character Conan Doyle avoided answering. The result is a wonderful combination of frivolity and darkness which achieves the one thing missing from much of Conan Doyle’s brilliant work: pathos. It’s quite the coup. BAFTA, take note. Of everything there is to enjoy about A Scandal in Belgravia, the cast, the writing, Arnold and Price’s music, the deerstalker gag and – oh Lord – the bed sheet, Paul McGuigan’s direction deserves real acclaim. His fluent visual style is a great match for Moffat and Gatiss’ nimble script, and the surprises his elegant direction provides are as integral a part of Sherlock’s success as the machine-gun dialogue and humour. So there it is. I may have gushed, but show me something more worthy of gushing over on the BBC right now. A tremendous piece of work from all concerned, now bring on The Hounds of Baskerville.