The UK’s coveted triple-A ratings could be under threat of being downgraded by the three chief credit rating agencies as concerns heighten over the soaring level of debt the UK Government will have to raise to finance its rescue of the troubled banking system.

Moody's Investors Service, Standard & Poor's and Fitch Ratings each rate the UK's long-term debt triple-A, but concerns among practitioners over the country's creditworthiness are starting to rise side-by-side with the level of UK Government debt to GDP.