UK ISPs filtering Web content

So, this is the first time I’ve knowingly had my Web access filtered by ISPs. I can see for myself that this is being done by O2 and BT, and there are apparently many other ISPs involved too. I strongly urge anyone reading this to write to their ISP and complain if they find they are also having their content filtered.

It is not the job of an ISP to perform filtering (with the possible exception of when the content is actually illegal), and I for one want to see this alarming trend reversed.

Edit: The Wikipedia page in question has been unblocked, which is good news. Let’s hope someone learnt a worthwhile lesson from this stupidity.