BBC One’s blood-soaked crime drama delivered its best episode of the series with this week’s tragedy-tinged tale.

Part Die Hard With a Vengeance, part Sherlockian mystery – and with a healthy dose of Shakespearean villain thrown in for good measure – Episode 5 centred on Inspector Reid’s right hand man Bennet Drake (Jerome Flynn), as old war wounds came back to haunt him.

We kicked off with the robbery of a jeweller’s coach, followed by the anonymous return of the haul save for one blue sapphire. Mysterious or what?

Next thing we knew, scraggly yet dignified war veteran Madoc Forster (Iain Glen) – Drake’s superior from his army days (Jorah Mormont and Bronn reunion anyone?) – turned up to question Drake’s loyalties, intrigue with Egyptian tales and make bitchy comments about Reid (Matthew Macfadyen). Unsurprisingly, it soon transpired that Forster was more than a little tied up in that whole thieving business.

As expected, the thrust of the story was Drake finding himself torn between his loyalty to Reid – who was being a bit of a madam this week – and his allegiance to his old comrades.

The episode was more of a character piece than a crime mystery and, though the plot wasn’t as convoluted as past week’s, the weaving together of all Drake’s threads – his wish to make an honest woman of prostitute Rose, his clashing with Jackson and some serious anger management issues – was expertly done.

Particularly fun was the fruity, imposing performance of Iain Glen, who got all the best dialogue. It’s not often you’ll hear lines like “For I have thrown open the doors of the firmament!” cropping up in your Sunday evening drama, and Toby Finlay’s script was crammed to the rafters with them.

Even Macfadyen had a bit more fun this week, getting tetchy with his underlings and demanding that the hungover Jackson be “dragged from his rank pit, trussed if need be!”. Once again, as evidenced by such lines, there was a hearty vein of humour running throughout – even a joke about coffee giving someone the runs made an appearance, albeit heavily disguised in Victorian vocab.

Another large part of this series’ charm is the chemistry between the three leads. As established from the first episode, Jackson and Drake aren’t exactly best pals and this week, they actually came to blows – making it two weeks in a row that Jackson’s received a beating at the hands of a fellow officer. In a surprisingly poignant turn of events, though, we found out Jackson was rooting for poor old Drake and, in the episode’s climax it was Jackson and his dab hand with a sniper rifle that saved the day.

Ultimately, Ripper Street works because we’re truly invested in the characters. But it’s also a series that doesn’t take itself too seriously and – in an age of grim Scandinavian police procedurals – that makes it a helluva lot of fun. Forget your sombre knitwear, we’ll take checked trousers and bowler hats any day.

Aired at 9pm on Sunday 27 January 2013 on BBC One.

> Order Ripper Street on DVD on Amazon.

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