The FTSE 100 had a slow start to the week, down 0.32% or 18.43 points to 5,684.94, following mixed sessions in Asia and the US.
The Bank of England is likely to increase its quantitative easing programme by £100bn to aid the economy as the government cuts spending, the Centre for Economics and Business Research says.
The leaders of 35 of the UK's biggest companies have expressed their support for the government's plans for spending cuts running into billions of pounds.
The UK recovery is losing momentum and will slow over the winter but chances of a double-dip recession are "exaggerated", according to the Ernst & Young ITEM Club.
The index of 100 leading shares has closed down on the day, with major insurers the biggest drag on markets.
Federal Reserve chairman Ben Bernanke has given his strongest signal yet that he will begin another round of quantative easing in the US, to try to acheive the economic "benefits" of the UK programme.
The government should commission a new assessment of the losses suffered by people who saved with Equitable Life, a committee of MPs has said.
The FTSE opened at 5,727 this morning, sliding 0.08% in early trading, although there was a raft of M&A activity among the UK's largest companies.
The Queen has canceled this year's Palace Christmas party in a show of "restraint" during the current age of austerity, according to a spokesperson.
The FTSE continued to feed off global optimism in early trading on Thursday, extending yesterday's 1.5% gain.