How exactly do you distinguish hate speech from free speech. If you stop these garbage channels, cant they lawfully or atleasht justifably stop anti islamic articles or cartoons?
Just a thought.
My thoughts on this..

I don't think it'd ever be easy to identify intended hate speech. The best thing to do is to allow all speech and refute possible hate speech. This would be easily possible on 'democratic platforms' where everyone gets an equal opportunity to speak, like on Internet forums or Youtube.
But in the case of 'elevated' or 'privileged' platforms, which are not accessible for refutation to the common folk either because
- of huge capital investement involved (1), (like a TV channel)
- or the platform has the umbrella of respect because of
-- 'popularity' (2) (say, like BBC, RDF or Pat Condell)
-- 'religion' (3) (which licenses any sort of indoctrination be it good, or bad since it is thought to be good like in the case of mosque or church sermons),
treatment could be different.
Islam channel satisfies 1 and 3
One way to address this this is to get this issue notified on equal platforms like the BBC, Guardian or Channel 4. When it's known that Islam channel and Peace TV are evidently engaged in radicalizing, and thus misusing their privilege, it'd probably make them less respectable so that even official Muslim bodies in UK would be forced to shun them. Then parents wouldn't allow children to watch them and the cable providers also would feel ashamed to broadcast them.
Btw, some time back, on BBC4 radio, Marcus Brigstocke, after he gave a strong bashing on Christianity, told "You wouldn't say that about Islam, eh?.... Here goes..all the beheadings, pedophilia, etc....Don't worry about me, I've done it before!"