They don't muck about down at London's Southwark Council. Quite right too:
Southwark Council routinely monitors the content of e-mail sent and received via its network for the purposes of ensuring compliance with its policies and procedures. Employees must never send or store e-mails or attachments that are obscene, indecent, sexist, racist, defamatory, abusive, in breach of copyright, encrypted or otherwise inappropriate. E-Mails of this nature sent in or out of the Southwark network may be intercepted and stopped by the system.
Southwark Council is not responsible for any changes made to the message after it has been sent. Where opinions are expressed, they are not necessarily those of Southwark Council.
This e-mail and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you are not the intended addressee, or the person responsible for delivering it to them, you may not copy, forward disclose or otherwise use it or any part of it in any way. To do so may be unlawful. If you receive this e-mail by mistake, please advise the sender immediately.
What, we wonder, does 'othewise inappropriate' mean? Looks like they've covered all the bases.