‘The Crimson Horror’ combined the skulduggery of Wilkie Collins with the froth of Jackie Collins via Moonraker. We shudder to think what goes on inside Gatiss’s head; but we’re imagining a cabinet of curiosities as eccentric as the insides of a 1970s television set.

Central to his mad intentions is the character of Mrs Gillyflower (Dame Diana Rigg), a sort of Joseph Rowntree figure whose social philanthropy hides a sinister purpose, as well as some crazy fetishistic suckling. Leaving her dramatic inhibitions somewhere in Westeros, Dame Diana proves a ‘happy medium’ for Gatiss’s brand of lurid nonsense – and we all know how much the Doctor likes one of those.

The scene where Gillyflower lectures the town on the moral turpitude in Bradford comes across like a hybrid of a Mary Whitehouse rally and that episode of The Simpsons when the monorail came to town. Comparisons to Whitehouse may seem far-fetched – although in this episode, frankly, nothing is too far-fetched – but it seems wickedly appropriate, in its 50th anniversary year, for the programme to feature a parody of the woman who rarely had a good word to say about it.

Had this been made in the Eighties, Mrs Gillyflower would have been played by Thora Hird. Of course, had it been made in the Eighties, it would have been even more camp… You thought Dame Diana Rigg giving it her best ‘ee by gum’ was astonishing? Imagine the addition of Kate O’Mara in a ginger fright wig.

This was Doctor Who looking up the footnotes of history, and then gleefully, perversely rewriting them. If you didn’t already know that Gatiss was weaned on the teatime terrors of Doctor Who’s past, you could have spotted it in the echoes of ‘The Talons of Weng-Chiang’ and ‘Ghost Light’, as a coroner took a little too much delight in noting the grisliness of a corpse, and a mysterious ‘monster’ was fed from under a locked door.

You wouldn’t want either of them served with onions indeed! Well, not unless the sight of a rouged-up Matt Smith, dressed in a union suit and doing a lot of jaw acting, does it for you – which, in fairness, it did it for blind Ada, whose tender ministrations to her unseen monster brought to mind the scenes with the blind old man in Frankenstein.

Such is the way with a Gatiss script. As with rats in London, you’re never more than six feet away from a textual allusion. Penny dreadfuls, ‘Brave heart, Clara!’…. Heck, it even quotes Larry Grayson at the end, as the Doctor has time to observe, ‘Look at the muck in ’ere!’

Still, there are plenty of innovations amid the parody. The image of the factory empty save for the trumpet-headed speakers is a good one, and it’s great fun when the regulation street urchin turns out to speak like a sat nav. Even better is the sight of the residents of Sweetville preserved under their bell jars, which plays on Victorian ideas of respectability and keeping one’s front parlour nice for display.

Some of the best moments come when the episode knowingly breaks with form, including the flashback sequence which plays out like a scratchy homage to early cinema. It’s all of a piece with the ‘what the butler saw’ flavour to the story, and, if it doesn’t feel quite so fresh as it might, that’s partly because there’s a lot of fourth-wall-breaking knowingness in Doctor Who these days, and it’s not uncommon to hear the Doctor giving a commentary on his own adventures. Which title is better – ‘The Crimson Horror’ or ‘The Repulsive Red Leech’? There’s only one way to find out!

We rather loved the episode, but then, we wouldn’t be watching Doctor Who if we were entirely averse to camp. Comedy of this kind depends on great energy in the playing, and it’s noticeable how speedily the one-liners zing past: ‘Attack of the supermodels’, ‘I’m gonna go play with my grenades’….

If we have one criticism, however, it’s the final scene and the appearance of Clara’s two charges who have rather too readily come to the conclusion that she is a time traveller.

Full credit to their History teacher and to their superior Googling skills; it certainly adds another dimension to the show to learn that Clara hangs around after her adventures to pose for a photo or two. Still, whether it’s a twist that embellishes the episode is debatable. We can’t be the only viewers, surely, wishing the young pair a speedy Cyber-conversion next week?

Aired at 6.30pm on Saturday 4 May on BBC One.

> Order Series 7 Part 2 on DVD on Amazon.

> Buy Series 7 Part 1 on DVD on Amazon.

Watch the Series 7 Part 2 trailer…

What did you think of ‘The Crimson Horror’? Let us know below…