from the bbfc faq:

Why are films on television cut?

There may be a variety of reasons. It could be to fit in with time and duration of transmission, or what is acceptable at different times of the evening. The BBFC has no jurisdiction over the showing of films on TV, and should you wish to comment or complain about films shown on television, you should do so directly to the BBC; or to the ITC (Independent Television Commission) if it is on the commercial channels, satellite or cable. Alternatively, you can contact the Broadcasting Standards Commission, 3 The Sanctuary, London SW1, which has a statutory complaints and research function

That's the BBFC's stance, they are only concerned with cinema and video regarding movies, they aren't responsible for censoring of TV movies.

It looks like Ofcom (the ITC's replacement) are a bit more lax now, the rating is now a guide for what time a movie can be shown.

From Ofcom.org.uk:

1.4 Feature Films and Other Acquired Material

"Where a British Board of Film Classification (BBFC) Classification exists for the version of a film or programme proposed for transmission, it should be used as a guide to scheduling. A BBFC video classification, rather than the cinema classification, should always be the guide where one exists."

I remember Carlton movies got into trouble for showing the uncut version of Bad Lieutenant a few years back. Most TV edits for movies are to fit it into a timeslot, or to show it a little earlier.

or in the case of ITV, to fit 40mins of adverts in.

my bad, just guess i been lucky when i caught films on network tv. which i gotta say i hardly ever watch anymore