I’m onto my fourth copy of Spearhead from Space. Having grown up on various repeats of it on ABC TV, I’ve now shelled out for the VHS release, the original DVD, the special edition DVD and now the Blu-ray.

I’d be annoyed about this, except the story keeps looking better and better. I remember my shock upon watching the first DVD release and seeing for the first time after many viewings that the fancy new Doctor’s (fancy Jon Pertwee) fancy new jacket was not black, but deep blue.

The reason why this story stands up to multiple scrubbing ups is… oh hang on, I’ll get to that later. Let’s instead watch the Doctor pick up a chick. Our hero may have just survived a traumatic regeneration, but as soon as he recovers, he wastes no time in proving his fitness. With the ladies.

His first goal is to warm up the show’s cool new lady scientist, Liz Shaw (Caroline John). Her new employer, the Brigadier (Nicholas Courtney), has been having a decidedly tough time breaking the ice with her; she smirks dismissively at everything he says and generally treats him like the village idiot. But then the Doctor breezes in with his new body, waggles his eyebrows at her and soon they’re getting on like a house on fire. “Do I really have to call you Miss Shaw?” he complains with mock indignation, and Liz giggles coquettishly and readily consents. The Brig needs to take notes for when he’s out on the pull.

But he needn’t worry. Turns out the Doctor was just buttering up this bird to get her to steal the TARDIS key for him. As soon as he gets it, he’s trying to abscond. Alas he can’t because the Time Lords have put the mockers on his beloved machine. As he creeps out to face the music, he slumps into a dejected funk and puts on the whole naughty schoolboy act. As a routine, it’s pure Troughton and a reminder that Spearhead from Space is not entirely the bag of new tricks for the series it’s often hailed as.

Sure, it’s the first story made in colour but on transmission most people were still watching in black and white. Yes, it introduces the new UNIT format, but that had already been trialled in The Web of Fear and The Invasion. And it’s very similar to The Invasion. Both feature quite a lot of stylish faffing about until the Doctor builds a gadget to beat the monsters. They even share locations.

The real difference with Spearhead is that it’s all shot on film. For the first time, the show’s characteristically patchwork style of cutting between video recording shot in studio and film sequences shot on location is dropped and we get a single, consistent look. In future years, the show would achieve this consistency by adopting video for the exterior shots, which only served to make a cheap show look cheaper. Spearhead remains the only classic Doctor Who with that cool, textured look of film which makes a cheap show look very swish indeed.

The difference it makes is palpable. Suddenly Doctor Who looks like The Avengers. Director Derek Martinus is energised to give us the best of his work on the show. We get sequences the likes of which we’ve never seen before.

In Episode One, the Brigadier is jostled by a scrum of newspaper reporters, and the camera is right amongst it in a way in could never have been in studio. In other scenes, he goes for high angles, peering down at his subjects, and rapid cuts to emphasize the action, which would have much harder to do in Doctor Who‘s traditional multi-camera style.

But it has its disadvantages too. Shooting interiors on location means they look like real places, because they are real places, rather than studio sets. That doesn’t mean they always look like the places they are meant to.

For instance, the halls and corridors of the BBC’s Wood Norton training facility never look like a hospital for a minute. UNIT’s makeshift lab has a number of moveable panels serving as would-be walls, helping hide the fact it’s in a big old hall of some kind. Goodness knows what would a truly alien setting – the interior of a Nestene spaceship, say – had looked like mocked up in a vacant office or something.

Indeed, what would Doctor Who have looked like if the producers had managed to convince the powers-that-be that the show should always have been shot on film? Or perhaps at least one story a year? Presumably interior sets would have been built at Ealing or something. But what would have happened to the electronic effects that Doctor Who came to depend on so heavily in the 70s and 80s? What about all that CSO? Spearhead‘s effects are all bangs and flashes and squibs. It’s hard to think about the show being full of practical effects. Nevermore a laser beam. Goodbye to roll back and mix.

It’s impossible to know how much of Spearhead‘s reputation relies on its total film look. But it does represent a sudden jump in quality from what Doctor Who‘s viewers were used to. I’m sure you’ve seen the previous adventure The War Games and whatever its merits (and there are many) it’s last few, mostly studio bound episodes look quite ramshackle.

By contrast, Spearhead offers some sequences which are startlingly effective. They would have been palpably different to even viewers still watching in monochrome. The most successful sections are in the mid episodes, with that sole Auton stalking through the woods, and jumping boldly in front of a UNIT jeep, killing the driver. And of course, there’s also the famous sequence in Episode Four when they break out of shop windows and hunt down early morning commuters on the street.

But these sequences would have been shot on location anyway. What we really need is a version of the story with all the interior scenes VIDfired so we can see what it would have looked liked if made the conventional way. And here’s the genius of it – it would be an excuse for yet another DVD release.

Get to it, BBC Worldwide! This sucker will pay for it again. I want to see how blue that jacket can get.

ADVENTURES IN SUBTITLING: This is not actually a mistake, I just want to point out my favourite of the Brigadier’s lines. It’s after Mrs Seeley is attacked, and he offers to:

BRIGADIER: I’ll lay on an ambulance.

Well, OK. If you think that will help…

LINK TO: Daleks in Manhattan/Evolution of the Daleks. Tentacles really are difficult, aren’t they?

NEXT TIME: The Repulsive Red Leech. Nah. On balance I think I prefer The Crimson Horror.