The Act was passed by the current Government after being formulated - some think in too much of a hurry - by the last. It aims to protect intellectual property.
Several of the objections centre around how exactly some of the sanctions would be put into place. How, for example, could you cut someone off from their Internet provider for piracy if they had a defence that said their computer's digital ID had been effectively faked?
You'd actually need a rock solid means of checking that every Internet address that appeared on your system - the location of a computer rather than the the email address - was genuine.
There are also issues surrounding what exactly someone means by an Internet Service Provider (ISP). If someone infringes copyright, the Act says, they can be cut off by their ISP.
The thing is, many ISPs buy their Internet provision from BT and re-sell it with extra services. This is perfectly legitimate, but if I were caught downloading loads of stuff I don't own then should my own ISP - with whom I have a contract, unlike BT - cut me off? Or should BT do it? Actually, since BT has the contract with my ISP, should BT be cutting my entire ISP off because the infringement is happening on its part of the network?