The Pound slid in late NY morning trading as Standard & Poor's affirmed its AAA rating for the UK, and maintained the country's negative outlook. S&P stated that medium term economic forecasts are less optimistic than the assumptions underlying the budget and the the UK government debt burden may approach a level incomparable with a triple A rating.
See S&P's release here.
The GBP/USD had already moved below an important level of support to start this week's trading at the 1.5080 area, and the news came as the pair tested that level as resistance. Following the news, the pair slid about 670 pips to the 1.5010 level.