The Footsie stood 35.1 points higher, with just a handful stocks in negative territory during the first hour of business.
Trading in New York lifted spirits as investors appeared confident that the US Federal Reserve will restrict its latest increase in interest rates to quarter of a percentage point tonight, rather than the half-point some feared.
That benefited mining stocks, which normally come under pressure when borrowing costs rise and the impact is felt on world growth.
Antofagasta rose 9.25p to 404.25p and Xstrata lifted 36p to 1914p, while Vedanta Resources added 21p to 1273p and Lonmin cheered 36p to 2757p.
Scottish & Newcastle was pulled lower with a fall of 1.5p to 504.25p.