Bad idea.
Even after 3 years living in the USA, I still can't quite get used to the complete and utter annoyingness of the advertising on TV here (or indeed, the TV in general). I hope I never do, because that will be a sign that my soul has finally died.
It's just weird, having the end credits of one programme go immediately into the opening credits of the next, only to be interrupted right away by an ad break. I think they even squeeze 3 breaks into the 11pm news (a half-hour show consisting of 2 minutes of local news, 10 minutes of weather, about 10 minutes of ads, and the rest devoted to what else but high school sports. Mehhhh.)
15+ minutes per hour of pharmaceutical industry adverts: "Ask your doctor about Blahtoxifen, side effects may include hallucination, loss of hair and in rare cases, death. Seek medical help immediately if you can't get it down after 4 hours."; ads for hooky weight-loss supplements: "Fatoffa works only as part of a calorie controlled diet with exercise, not approved by the FDA"; sometimes the same ad run twice, back to back; those fucking annoying cleaning product ads with the shouty guy; then the network runs a trailer for one of their upcoming shows and I think "yay, ads over, time to sit down again" only to have MORE FUCKING ADVERTS to follow. They've figured out that people will go back to their seat or stop fast forwarding when the trailer finishes, so they've stuck more ads in after it. Not to mention the adverts where the volume level SUDDENLY INCREASES WITHOUT WARNING!
GAAAAH!!! <--- this is how you will feel after OFCOM makes these changes. All. The. Time.
"television has yet to implement the big fucking annoying ad, rolling across the screen in front of the programme you're trying to watch."
Heh, if only. Right after the aforementioned annoying ad break, you'll be about 15 seconds into the programme again when the ENTIRE CORNER OF THE DAMN SCREEN is suddenly occupied by a fully animated, highly distracting trailer ad for some other show. This doesn't happen often, yet, but it does already happen here.
Ironically, we *could* avoid most of this by having a PVR and skipping the ads, but we don't actually watch enough TV to justify buying one.