To recap, Simon Pegg was the creator and writer of the massively successful Shaun of the Dead, and Charlie Brooker is creator of Dead Set, the five-part zombie TV drama which was on the week before last every night on E4. In Shaun of the Dead, zombies of course shamble in the traditional manner, in Dead Set they run, snarling like feral beasts.
In an article last Tuesday Pegg argues that zombies should not run. In an article today (half way down that page) Brooker replies as best he can to the charge (the whole debate is charming). Pegg's argument is thoughtful:
The fast zombie is bereft of poetic subtlety. As monsters from the id, zombies win out over vampires and werewolves when it comes to the title of Most Potent Metaphorical Monster. Where their pointy-toothed cousins are all about sex and bestial savagery, the zombie trumps all by personifying our deepest fear: death. Zombies are our destiny writ large. Slow and steady in their approach, weak, clumsy, often absurd, the zombie relentlessly closes in, unstoppable, intractable.
However (and herein lies the sublime artfulness of the slow zombie), their ineptitude actually makes them avoidable, at least for a while. If you're careful, if you keep your wits about you, you can stave them off, even outstrip them - much as we strive to outstrip death. Drink less, cut out red meat, exercise, practice safe sex; these are our shotguns, our cricket bats, our farmhouses, our shopping malls. However, none of these things fully insulates us from the creeping dread that something so witless, so elemental may yet catch us unawares - the drunk driver, the cancer sleeping in the double helix, the legless ghoul dragging itself through the darkness towards our ankles.
Brooker's counter-arguments are merely pragmatic, but compelling in context.
They HAD to run or the story wouldn't work. The outbreak had to knock the entire country out of action before the producers had time to evacuate the studios.
We had to clearly and immediately differentiate Dead Set from Shaun of the Dead, which had cornered the market on zombie-centric horror-comedy. Blame yourself, Simon: if you'd made that film badly, it wouldn't have been so popular, and drawing a distinction wouldn't have been an issue. Each time one of our zombies breaks into a sprint, it's your own stupid talented fault.
...Running zombies are, to be frank, cheaper than stumbling ones. You only need one or two to present a massive threat.
(But read them both in full if you like zombie stories)
ETA metafilter have a discussion here.