The global pool of government bonds with triple A status from the three main rating agencies, the bedrock of the financial -system, has shrunk more than 60 per cent since the financial crisis triggered a wave of downgrades across the advanced economies.

The expulsion of the US, the UK and France from the “nine-As” club has led to the contraction in the stock of -government bonds deemed the safest by Fitch, Moody’s and Standard & Poor’s, from almost $11tn at the start of 2007 to just $4tn now, according to Financial Times analysis.

The shrinkage, largely a result of the US’s downgrade by S&P in August 2011, is part of a dramatic redrawing of the world credit ratings map, which is encouraging investment flows into emerging markets and forcing investors and financial regulators to rethink definitions of “safe” assets.