It won't happen until somebody is prepared to pay for it. Recabling the entire country would cost a vast amount of money. There's currently no company that's prepared to make that sort of investment.
If private enterprise won't foot the bills, the only alternative is government finance. It's easy for people to say that the government should fund the infrastructure, but the idea becomes less popular when it's pointed out that we'd all have to pay much higher taxes (in addition to those which are already on the way, in the next few years, to repay all of the money that the UK has recently borrowed).
If you want fast internet access, move to South Korea. Their government has got plenty of money in their reserves, plus a population which is largely congregated into metropolitan areas. The South Korean government has been able to find the funding to develop a broadband communications system, based upon fibre optics plus wireless access, providing a (minimum) 100Mb/s service. Already 95% of homes have access to this service, and the country is well on the way to achieving its target of 100% access by 2012.
In contrast, the UK government has massive debts and a population spread over lots of small towns and villages. The UK government has provided some infrastructure funding, but only to ensure 100% access to a (minimum) 2Mb/s service by 2012. (i.e. the South Korean target, for the same time, is based upon speeds 50 times as fast as those in the UK).
Technology experts, interviewed on BBC World Service, recently estimated that the UK won't be able to match South Korea's service until 2035 at the earliest.
Chris