I am not sure if you clicked on the link to;
http://www.kitz.co.uk/adsl/caps.htm from the post LOTR mentioned...

But on that site it lists a lot of Internet Providers such as BT, Bulldog, Tiscali, wanado, demon and AOL(the ones I would consider to be the major players in Internet Hosting) and says they all shape the bandwidth.

In fact the only 1 out of 50+ providers that doesn't cap or limit your usage seems to be a company called Eclipse Flex...

On that note I would take great care in selecting your next ISP if you are an avid P2P user.

After your search will you please post your findings on here as soon, I too will be looking for a UK provider that truely offers 'unlimited' brandband...

Many thanks
Marc