According to the BBC News the largest ISPs have agreed to start clamping down file sharers with people being warned and then potentially having their either slowed down or cut off.  This includes Carphone Warehouse who originally had declined to tow the line as far as the BPI was concerned. 

The concerning thing is that there appears to be no means to dispute an accusation of file sharing. For example, if they pickup on a transfer of music that I legitimately own from my home PC to my work machine over the Internet how I can defend myself?

It will also be interesting to see if people start to migrate their Internet access away from the major players to smaller ISPs who are not currently party to the agreement.