This is not an easy question, and depends on what content you're talking about. It also depends upon the nature of the allegations.
For obvious reasons, you designing and constructing pages which contain content selected and uploaded by you, which breaches statute law, common law or legal regulations, will leave you more exposed to legal sanctions than simply hosting a site for a client which contains content uploaded by your client.
Provided your situation falls into the latter category rather than the former, you should be okay, with certain exceptions.
If (God forbid) the site you are hosting contains content, the display of which constitutes a serious criminal offence (i.e.: child abuse, terrorist material etc.), even if you didn’t upload the material (and whilst you may not be directly guilty), you may be drawn into any investigation by virtue of you having hosted the site containing the material.
Similarly, hosting a site which contains material uploaded by others, the display of which may amount to defamation, could leave you liable as a “secondary publisher” for libel. Provided you can prove that:
a) you did not know about the defamatory nature of the material and;
b) you removed it as soon as you found out, and;
c) the client was not acting under your control when they posted the material,
…you should be okay (S19a & b Electronic Commerce (EC Directive) Regulations 2002).
Any assessment of the above should quickly reveal that this is a potential (and potentially very nasty) minefield. Common sense, as is usually the case, is the key.
Points to note:
a) Obviously, don’t upload material to a client’s website which you cannot prove you or your client has a licence to use;
b) If you have misgivings about material provided to you by your client for uploading by you, DON’T give them the benefit of the doubt;
c) Once the site is up, if you have misgivings about anything you discover which has been uploaded by others, once again, DON’T give them the benefit of the doubt. If you can’t verify the material is legal and/or licensed very quickly, take it down immediately.
Final point, and perhaps a rather curious anomaly, don’t take this as an implied duty to police your clients’ websites. The fact of you doing so could actually defeat any defence plea under S19 (as you spending more time reviewing your clients' sites flies in the face of any argument that you were unaware of what they were doing).
Once again, common sense, and open eyes should keep you safe.
Dean