and then there's the part where the ISP has to pay part of the cost for sending takedown notices

Internet cut-off threat for illegal downloaders | Technology | guardian.co.uk:

But today the government will take the unusual step of proposing much stricter rules midway through the Digital Britain consultation process. Illegal filesharers will still get warning letters but if they continue to swap copyrighted material they could have their internet connection temporarily severed, although it may be possible to retain basic access to online public services.

A similar law in France under which filesharers could be cut off for up to a year was recently kicked out by the country's highest court as unconstitutional. In the UK, privacy groups are likely to challenge any similar legislation as contrary to human rights law.

The power to introduce technical measures, meanwhile, will rest with the secretary of state, not Ofcom and their introduction will not rely upon an arbitrary 70% reduction in piracy but be up to the minister's discretion as he tries to secure the future of the UK's creative industries.

"The previous proposals, whilst robust, would take an unacceptable amount of time to complete in a situation that calls for urgent action," according to a draft of the government's new plan.