Sherlock, TV review: 'Series 3 finale delivers the goods'

A dizzying trip round Baker Street’s patriotic front

Benedict Cumberbatch as Sherlock Holmes (PA)

If you require more than just explosions and car chases from your weekend viewing (get you!) then the concluding episode in this current run of Sherlock (Sunday, BBC2) delivered the goods. It had intelligence, humour and obscure fanboy references galore.

After the bromantic lull of last week's wedding episode, in which the mystery plot was half-drowned in sentiment, there was reason to fear Sherlock had gone soft. We should have had more faith. Sherlock always plays the long game and this week was a pay-off that more than justified its set-up. The clue was in the episode title. "His Last Vow" made reference not only to Arthur Conan Doyle’s "His Last Bow", a patriotic spy story from 1917, but also to the vow made by Sherlock in his Best Man's speech: "Mary and John, whatever it takes, whatever happens, from now on I swear I will always be there. Always."

The challenge to Sherlock's loyalty and his patriotism came in the form of Charles Augustus Magnussen, a foreign newspaper proprietor-cum-master blackmailer who had the audacity to insult the English while urinating in Sherlock's fireplace.

"You can do what you like here," he mused as he tinkled. "No one's going to stop you. It's a nation of herbivores." Fans of Borgen and The Killing have been awaiting the arrival of Lars Mikkelsen as Magnussen ever since the closing shot of episode one, but this performance was enough to send a shiver down any spine - a viscerally repugnant cross between Hannibal Lecter and Rupert Murdoch.

Magnussen wasn't the only new character to be introduced. This was the most dizzying, lysergic episode yet, in which Sherlock's "mind palace" became our home from home, and a similar mnemonic device would be needed to recall how it all slotted together. A few old frienemies dropped by to say hello and we developed deeper insight into the two leads. We now know what tickles Watson's fancy and that Sherlock's fancy will always remain reassuringly untickeld.

So yes, Sherlock requires attentive viewing, but it rewards your attention tenfold. There was enough detail in this episode to justifying watching it again and again, once weekly, until series four starts next year.

Video: Sherlock - Series 3