The UK's credit rating has been revised from negative to stable by S&P, further consolidating its ‘AAA' status and boosting the coalition government's economic plans.
The UK's economy grew at 0.8% between July and September, higher than most economists had expected.
The index of 100 leading shares was down a third of a percent just after opening, as the markets await figures for UK growth.
Bank of England Governor Mervyn King has thrown his weight behind breaking up the banks as part of reforms to protect the taxpayer from another financial meltdown.
The US dollar has sunk to a fresh 15-year low against the yen after the G20 nations pledged to avoid a currency war.
Ed Miliband has called for financial services regulation to be tightened up and a reshaping of the banking sector to encourage small business growth.
Britain's best years are ahead, the Prime Minister told delegates at the Confederation of British Industry (CBI), in the wake of the worst financial recesssion since World War II.
David Cameron has announced a "wholesale change in attitude" from the government to encourage business growth and infrastructure investment.
The FTSE 100 rose 0.9% to 5,791.10 in early morning trading as a weaker US dollar provided support for mining stocks.
Business leaders have issued a fresh warning today about Britain's competitiveness, releasing a survey of leading executives which suggests the country is slipping behind its international rivals.