Rating agencies, which measure the credit worthiness of companies, became the latest in the line of fire from the UK's powerful Treasury Select Committee for reacting too slowly as the Northern Rock debacle unfolded and not "flashing out warnings" on the potential risks ahead of time.

The probe into the run on Northern Rock widened a month ago to include hedge funds, private equity transactions and ratings agencies after the committee asked for new evidence for its investigation and indicated that it could call back parties already interviewed for fresh questioning.