Weakness in mining stocks offset gains in banks to leave Britain's top share index 0.1 percent lower at midday on Thursday, after the Bank of England left interest rates and quantitative easing unchanged, as expected.
By 1218 GMT, the FTSE 100 was 5.17 points lower at 5,528.04 after it closed 49.15 points, or 0.9 percent, higher on Wednesday, its fourth day of gains.
Banks provided the main support for the blue-chip index, with Barclays Standard Chartered, Royal Bank of Scotland and Lloyds Banking Group gaining 2.0-3.5 percent, though HSBC fell 0.2 percent.
Markets were unruffled after the Bank of England kept interest rates at a record low of 0.5 percent and made no increase to its scheme of pumping money into the economy to get it back on its feet.
"Absolutely no surprise whatsoever," said Keith Bowman, analyst at Hargreaves Lansdown. "You would have to say with the central bank only just suspending its QE programme, the fact that they have made no changes there, it certainly is not a surprise. Rates are pretty much expected to stay where they are probably until nearer the end of the year, even into 2011."
The European Central Bank was set to announce its latest monetary policy decision at 1245 GMT. With no change expected, investors will eye a news conference at 1330 GMT.
"(Investors will watch for) any possible hints from the ECB about their thinking on when they will end the period of extraordinary loose monetary policy," said Henk Potts, market analyst at Barclays Wealth.
Investors were refocusing on U.S. jobs data due Friday for clues to the outlook for the global economy.
Miners were the biggest drag on the blue chip index as metal prices weakened, taking the shine off a sector that had helped drive the market higher this week.
Rio Tinto, Xstrata, Lonmin, Anglo American and BHP Billiton fell 0.4-1.1 percent.
Schroders was the top blue chip gainer, up 4.7 percent as the investment company reported an 11 percent rise in full-year profit driven by rising assets under management and higher net inflows from clients.
But investors reacted negatively to results from Amec, although the oil services and engineering group posted a 13 percent rise in full-year EBITA, with Deutsche Bank highlighting a relatively weak topline outlook.
Highlighting the headwinds facing the economy, house prices in Britain fell 1.5 percent in February, the first drop since June last year, mortgage lender Halifax said.
