The BBC played a risky game with this short series. Aimed very directly at the people that love Doctor Who, they built it up to be something enormous. Steven Moffatt spent a lot of time raving about it on Twitter, and between him and Mark Gatiss, interviews, blog posts and adverts, it was hard to escape from the glare of the descending Sherlock.

When it finally arrived, it turns out, the risk was absolutely worth it. Written to perfection, with a fine story and strong (as ever) dialogue, plus two extremely well-chosen actors in place, it’s hard to see where this episode could have been improved upon.

Starting with Watson is important. He is our in. John Watson is very sweet, damaged by war, desperate for action, ultimately a good guy. He needs somewhere to live. He bumps into someone who knows someone, and thus we (and John) are introduced to Sherlock.

It’s hard to know what to make of someone when your first glimpse of them involves a riding crop. The lab girl clearly likes him (although I still see her as that nurse out of Casualty), and I really liked the thing with the lipstick, as miniscule a part of the episode as that was.

So, Sherlock has John all sussed out, and the best sequence of the entire episode plays out for us - SH explains how he came to his conclusions about Watson, impressing his new friend, but he gets one bit wrong. Already this has set them up to have a great relationship.

The police have a case on their hands, and Sherlock is interfering via text message. This is no deer-stalker rip-off of some classic literature. This is Sherlock, similar but changed, crafted into something new and almost painfully modern.

What is it about the exceedingly clever but vulnerable male that grabs the nation’s hearts? The Doctor is an alien, doesn’t fit in, tries to reach out to humans but is always left a little bemused - as they are to him. Sherlock describes himself as a “high-functioning sociopath”, clearly unable to understand why people find him baffling, whilst simultaneously wondering what on earth goes through these human heads. Even someone as remote as Superman fits the “male, good sense of humour, high intelligence, eager to save the planet, seeks human to explain this crazy world” criteria. Whatever it is, it sure is popular on our TV screens.

Regardless of steretype, the new Sherlock keeps on breaking the bonds of his literary counter-part. He uses umpteen nicotine patches instead of drugs. He sends text messages to a distant Watson just because he is bored. John himself blogs instead of writing the books we know and love. The blog actually exists, and whilst it is interesting to read, I wonder if it is entirely necessary. The only bit I particularly enjoy is seeing Sherlock’s responses.

The story for this opener is supremely strong. A string of suicides seem unconnected, but are eventually tracked down to a serial killer. Sherlock, and his new found friend, investigate at a rapid pace, all the while finding out about each other. Watson learns that he doesn’t need to walk with a stick, and Sherlock learns… well, actually he just has a jolly good time.

The police and their attitudes towards their “consulting detective” show frustration but a grudging respect. Without him, they would be nowhere, but with him, they are running around without a clue as well. I must say, I guessed that it involved taxis from quite early on, and I was a little disappointed when the police realised the phone was in the property but didn’t connect it with the cabbie no one ordered walking up the stairs.

I do not claim to have figured it all out, though, not by a long shot. Using the on screen text to give an insight into what Sherlock is seeing was a great idea - it allowed us in but didn’t spoil his big reveals. So what if her coat is wet? Oh right, yes, that means she came from Cardiff. Duh.

The big showdown was also great. Sherlock can’t resist playing the game, and in the end, he needs his friend to save him/stop him (echoes of the Doctor here too). He also shows a quite disturbing side when trying to get the name of the mastermind behind it all. Moriarty. He is the big bad.

A great story and great casting. Una Stubbs is inspired, by the way, even if she only has a tiny part in it. Martin Freeman plays the straight man well, just like he did in The Office. And Benedict, what to say about him? He clearly has the greatest name ever, and immediately people were wondering why he hadn’t been cast as Doctor Who. He has that great flippant yet loveable thing going on. There were reports that he had been in talks for the DW role, but didn’t like the idea of being on people’s lunchboxes. Why is this such a big deal? If he had been Doctor Who, he wouldn’t have been Sherlock, and I am more than happy with the way things have turned out.

We’ve got an excellent Sherlock and a strong John. The relationship between the two is set for great things, it’s just a hope that the stories are strong enough to hold them up.