Here in the US, the dumbing down of the media (and the population) serves several purposes. If you've read Orwell's 1984, you can see most of them represented there. Things like distracting the people from the real issues, entertaining them with mindless garbage to keep them happy and dumb so they won't notice all of the bad things the government has in mind for them, using the media as a propaganda tool instead of a way to educate and enlighten. And of course, it's a great recruitment tool for the military industrial complex. I'm guessing maybe the dumbing down of the media (and the population) could serve the same purposes in the UK.