It seems rather apt that the penultimate episode of Ripper Street (BBC One, Monday, 9pm) should be titled Our Betrayal.

Ever since the second series of the Victorian detective drama jumped schedules from Sunday to Monday, fans had worried that something was afoot. And sure enough, with all the business sense of opening a designer boutique right next door to a pound shop, Ripper Street's grown-up entertainment was trounced in the ratings by the juvenile antics of ITV's I'm A Celebrity... Get Me Out Of Here.

Conspiracy theorists among us wondered if this was a deliberate ploy by the BBC to create an excuse to axe the show, as those lovingly recreated, filthy 19th-century neighbourhoods were surely a burden on the Beeb's budget. Ripper Street had done well enough at its original transmission time, although its graphic violence and decidedly adult storylines had, even after the 9pm watershed, ruffled a few petticoats for the Sunday period drama brigade. The move to Monday felt like an undeserved, points-docked relegation to a lower league.

Part of the show's appeal is its combination of this historical and, in its own way, literary subject matter with a post-Sherlock fascination for clever detective work. Even as individual plotlines drew from the popular culture of the era - stories built on variations of Jack the Ripper and Fagin-style child gangs, political anarchy and Irish nationalism, eugenics and the Elephant Man - the strongly-drawn characters provided arcs to carry us from the beginning to the end of both eight-episode series.

The dynamic of Ripper Street lay in the struggle between the old and the new. The female characters, be they a brothel madam such as Long Susan (MyAnna Buring) or crusading councillor such as Jane Cobden (Leanne Best), were independent of mind and written as precursors to the suffragette movement. The policemen were either old-school, fists-first monsters like Chief Inspector Fred Abberline (Clive Russell) or those like Detective Inspector Edmund Reid (Matthew Macfadyen), eager to try out modern, more scientific methods.

How sad it is that, just as these deeper themes were coming to fruition, embedded firmly in individual character dilemmas, the BBC, like Jack himself, ran a deadly blade across Ripper Street's throat.

The first episode of the two-part closing story saw everyone in emotional turmoil: Reid loosening his emotions to Cobden; Susan forced to give herself to her bullying landlord; her surgeon/loose-cannon husband Homer Jackson (Adam Rothenberg) wondering how to win her back while thrown by the arrival from South Africa of his rogue brother; young Constable Flight losing his soul to Reid's cop nemesis from Limehouse division, Jebediah Shine (Joseph Mawle channelling the sadistic spirit of Daniel Day Lewis in Gangs Of New York into something wonderfully evil).

At the centre of Series Two, however, is Sergeant Bennet Drake, a career-best performance from the underrated Jerome Flynn. Torturing himself over his wife's death, Drake was seen being battered in a backstreet gambling den. Tied to a post, blood dripping from his brow, he was an almost Christ-like figure in his suffering.

We've got one final episode of Ripper Street to come on Monday before - like Joss Whedon's Firefly and Judd Apatow's Freaks And Geeks - it is left to live on in cult veneration in fans' DVD collections. Perhaps early talk of reviving the show via a co-production deal with LoveFilm will come to fruition. But as for the BBC executives who made the decision: banish them to the jungle they fear so much.