While the Digital Economy Act was passed in the UK last year, the UK government can't force ISP's in the region to do anything beyond a letter writing campaign against those accused of infringement. The problem lies in the fact that the government needs to make certain changes to the law before it goes into full affect.
The Digital Economy Act, which passed in 2010, gave copyright holders the power to send a "copyright infringement report" to ISPs with evidence of unauthorized downloading on their network. When this happens the ISP is required to notify suspected subscribers about the allegations, provide education about where legal alternatives can be found, reveal evidence, and offer guidance on an appeal pathway.
One of the reasons the DEA hasn't been fully implemented is because BT and TalkTalk asked for and were granted a judicial review of the act in March 2011. Last month the Court of Appeal ruled against their challenges to the law, but one concession they did get is that they would not be forced to pay for 25 percent of the costs when alleged infringers appeal to an appeal board that will be established (you can read the court's ruling here).
Of course this means that the previously-published Draft Statutory Instrument outlining the sharing of costs has to be amended before it can be fully enforced. That means the UK government will need to amend the previously-published Draft Statutory Instrument outlining the sharing of costs. Regulatory body Ofcom will need to amend the draft code under which it will enforce the law and they say they can't do that until the government makes its amendments. While Ofcom has suggested that, after a few years of this letter writing campaign being used, there could be harsher penalties facing infringers (such as throttling and traffic shaping), the agency admits that such changes would have to make it past legal test in UK and European Parliament committees.
A BT spokesperson said that, with this new ruling, it will figure out what its next move is. If there is another legal move it would most likely be an appeal to the European Court of Justice.