Investigation begins into credit rating 'blunder'

French and European investigations were under way yesterday after a "blunder" by a credit rating agency wrongly suggested that France had lost its triple-A debt rating.

The French Finance Minister, François Baroin, said the mistake by Standard and Poor's (S&P) – although rapidly corrected – was "shocking". The European Commissioner for Financial Affairs, Michel Barnier, spoke of a "very serious incident". The mistake on Thursday evening intensified speculation against French government debt and led some French and European officials to talk of a possible market "conspiracy" against France and the euro.

"When you know that many billions of euros can be traded every second on the bond markets, you have to ask who might benefit from false information of this kind appearing ... on trading screens all over the world," one French finance ministry official said.

An electronic message from S& P said: "Alert, French Republic downgraded." A few minutes later, the message was cancelled and described as a "technical error". The agency added that France's prospects remained "stable".