Regarding Mr E and a comment about posting porn, ie, it is not illegal to do so.
I would take a look at The Obscene Publications Act 1959.
I would very much doubt expert witness' are available as to its literary, artistic or scientific merits.
Just because its there and readily accessible does not mean it is not illegal. That's the problem with the tinterweb, what is legal in one country ir likely highly illegal in another country where it is viewed.