Torchwood... well, sort of

I'm intrigued to see which bits go in their "edited down to be suitable for children" version of Torchwood. Have the episodes been created from the start in the knowledge that they need to be cut later, so the "naughty bits" are all extras, and things that the plot can survive without? Or is the BBC just going to take the scissors to the episodes left, right and centre, not caring if they cut out bits that were essential to the plot. The latter appears to be the approach taken when editing the violence out of American TV to make it suitable to shown over here before 9. (I'm thinking of episodes of Angel, and even some of Buffy, that made no sense at all because of the way they had been been edited. It made me quite cross. If you're having edit virtually every episode, maybe you're showing it in the wrong time slot!)

Does anyone know what the guidelines are on exactly what can be shown before the watershed? I imagine there must be quite a specific list, detailing exactly how much violence (or sexual references or swearing etc.) are allowed before you Go Too Far. I fancy it could be quite an amusing read.