Well, there are two versions of this film in existence: The theatrical version, in which the Ashton Kutcher character survives, and the director's cut, in which Kutcher... doesn't. I have the DVD, so I didn't watch Film 4's print, so which one did they use?
The directors really prefer the one in which Kutcher zaps himself out of existence, though a 'happier' ending was imposed on the theatrical print. I have the US DVD, which contains both edits, though I'm not sure if this was carried over to the UK release. Could anyone possibly confirm?
As for editing, I doubt the film was cut for any reason, given that it was broadcast after the watershed (where it belongs - this movie is very heavy in places!). It just depends on which version was screened, and which version you're used to seeing.
The only version I saw was the one where he kills himself in his mum's womb. However, the version I saw on FilmFour was very different! Half of the scenes in the prison were cut out completely. There were various other edits too that I can't remember right now.
But the ending surprised me. It was all happy. Everyone got a happy ending and Kutcher was alive and well and had a job in the city. It didn't fit in with the rest of the film at all and just had that feeling of them being forced to write a happy ending Not sure whether that was actually the case or not, but it came across like that!
Aha! In that case, it's clear Film 4 went with the theatrical print.
Apparently, the UK DVD contains only the much superior (IMO) director's cut with the not-so-happy ending, so it's a surprise to find Film 4 going with the 'lesser' version.
Still an extraordinary film, whichever version you happen to see...