The UK High Court recently imposed court orders forcing router providers to filter out material that they has (in a trial) proven to be in violation of copyright laws. While this feels like a step in the right direction (from a government that often seems woefully out of touch with technology) they could have easily done better.
The first hole in their scheme is TOR and VPNs; which allow people to circumvent this router-level filtering (you can try this by downloading tor at torproject.org and then go to ukispcourtorders.co.uk, and then use TOR to visit one of those sites – result!).
The second hole is that they're blocking specific domains. The problem with this is that a domain costs under £10 and takes less than an hour to set up/switch your site to.
So how could they improve. Well the obvious way is to put pressure on web hosting companies to vet sites that they host, to ensure that they don't violate copyright regulations; the difficulty is this requires multi-national co-operation between countries as these sort of sites are normally not hosted in the UK. Another (more controversial) measure is to DDoS these sites (distributed denial of service attack), which would essentially force them offline (presuming you got cloudflare.com – US based DDoS protection to terminate service to them – copyright regulations) and make it impossible for the content reviewed.
I think that while the High Court is (at least) aware of the problem, they are almost trying to stop the circulation of counterfeit materials by policing any potential customer – as opposed to stopping the distributer of these materials.