The FTSE 100 Index crept into positive territory today as investors awaited a decision on America's vast economic stimulus drive.
The verdict on whether the US will continue pumping $85 billion (£53 billion) a month into the world's biggest economy will be announced after the London market closes.
In the meantime, the FTSE 100 Index improved by 24.7 points to 6510.3 as it resumed the upward trend seen on Monday.
The decision will be one of Ben Bernanke's final acts as chairman of the Federal Reserve.
Retailers dominated the fallers board in London as fears mounted that December has been weaker than expected for many chains.
Marks & Spencer slumped by more than 2 per cent, off 11.2p to 441.1p, while Sainsbury's was off 8.75p at 369.85p and Tesco dipped 3.5p to 320.9p.
BP shares were 2.45p higher at 467.45p, despite the oil giant announcing that it will write off more than one billion US dollars in costs associated to an unsuccessful Brazilian well. However, this news was offset by a significant oil discovery in the Gulf of Mexico.
Rival company Royal Dutch Shell moved in the opposite direction, falling 2.25p to 2175.25p.
