It's this Libel and Defamation law that has often contributed to the allegations of censorship. Fundamentally some of this is built into British culture, and is significantly different to US culture where "free speech" rules supreme. But it's the bleeding of US culture into that of the UK though the media+internet that leads to a more vocal debate around these issues than before.
To quote form the Wikipedia article below:
"English defamation law puts the burden of proof on the defendant, and does not require the plaintiff to prove falsehood. For that reason, it has been considered an impediment to free speech in much of the developed world."
The world is so much more connected now it's inevitable that cultural and legal differences will reduce and some sort of equilibrium will be found.