However, the Royal Mail (the British Postal Service) is working on a prepaid, pay in cash, highspeed internet service.
You see, post offices in the UK are a lot more like Banks and some are even general convenience stores than that are in the US. They even offer savings accounts, right there at the Post Office, with a very good interest rate (actually I believe I still have a Post Office account somewhere).
For about $30 per month you get speeds up to 8mbps over a cable connection and a wireless router.
See more at the Post Office Web Site