Standard and Poor's downgrade Britain

This doesn't look very good, it's no wonder there's nothing on BBC

One of the world’s biggest credit ratings agencies said that Britain’s ongoing “weak economic environment” and Gordon Brown’s failure to properly reform the financial system had led to its unprecedented decision to “downgrade” Britain’s banks.

The warning from Standard & Poor’s sparked an immediate slump in the stock market and the value of the pound

More in the Telegraph

This might be how they work out the rating - there's bound to be somebody somewhere in the blogosphere who will have more information later, as well as a detailed explanation.