Think-tank warns Chancellor to keep his hands of QE windfall This would risk undermining the credibility with which he is managing the UK public finances. The think-tank said a weaker growth outlook and lower than expected tax revenues meant Mr Osborne would probably have to abandon his target to see debt as a percentage of GDP falling by 2015-16. It warned that he may also have to announce further spending cuts and tax rises to meet his main fiscal target of balancing the structural current budget by the end of a five-year rolling period. That would potentially extend austerity to eight years from the five originally intended after the 2010 general election. Increased pressure on the public finances puts Britain's treasured AAA credit rating at risk. Moody's said earlier this month that it would look again at the rating early on in the new year, after the Autumn Statement forecasts. In better news for the Chancellor, the Office for National Statistics is expected to confirm its initial estimate that the economy grew by 1pc in the third quarter, after receiving more data on the period. The CBI also reported a rise in business confidence in Britain's services sector, while Experian said business insolvencies were 8.7pc lower in October, compared with a year earlier.