Ahead of Sherlock‘s return this autumn with a second series of three new feature-length episodes, the hit first series begins a repeat run on Wednesday night at 8.30pm on BBC One. Receiving glowing praise from both critics and audience, the show breathed new life into the Great Detective and the crowded TV crime genre. Here we take a look at what made the newest incarnation of Sherlock Holmes such a success.

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Central to the show’s success is clearly executive producers Mark Gattis and Steven Moffat’s love of the characters. As self-proclaimed Sherlock Holmes geeks, the two lead writers may have moved things into the 21st century, but their reimagining kept remarkably close to the gaslit source material. The result is a Holmes for the hashtag generation, but it’s unmistakeably Holmes.

Yes, he wields an iPhone and he has a cool coat, but he still uses the same deduction and logic he’s renowned for. Perhaps most wisely of all, the series concentrates on what lies at the heart of Sir Arthur Conan Doyle’s original stories – the friendship between a ruthlessly clever man and his loyal companion, having adventures and solving crimes – and has both heroes perfectly cast.

Benedict Cumberbatch’s interpretation of the character is spot on. Aloof, mercurial and eccentric, he’s a young Holmes but just looking at him you feel a certainty that there’s a supreme intellect whirring away behind those cold blue eyes. Arguably Martin Freeman’s performance as Watson is even more impressively nuanced, as a battle-scarred veteran struggling to adapt to civilian life but still thirsting for the thrill of danger.

Put together they make for a magnetic onscreen duo, swapping quick-fire banter as each man attempts to not only understand the nature of the crimes they’re solving, but each other’s little idiosyncrasies. It’s during these exchanges that you notice just how truly well-crafted Moffat’s writing is. By turns funny, sinister, and always so clever that you get the feeling there’s not a wasted word in there, you’d expect nothing less from the Doctor Who and Jekyll scribe.

On top of the cerebral sleuthing, Sherlock delivers smartly directed action aplenty, with the standout example being the chase in Episode 1, ‘A Study In Pink’. It’s not only a whirlwind dash through London but also Holmes’ mind, as we see him calculating a route, timing traffic lights and remembering roadworks, all while leaping across rooftops and down alleys. The sequence is beautifully shot, breathlessly edited and it captures the physical and mental prowess of the character.

In fact, the whole show has a forensic attention to presentation, with technology and Holmes’ equally robotic thought processes as smoothly integrated into shots as into the plot. Neat visual touches like text messages drifting and dissolving above phones and Sherlock’s mind deciphering clues give the audience a far greater intimacy with the character than we’ve had in any previous adaptation.

Striking a faultless balance between referencing the classic and updating the old, Sherlock drew in die-hard fans and created new ones on its original airing last summer – all of whom are probably still on the edge of their seats waiting for the resolution to that cliffhanger…

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