* FTSE 100 down 0.5 pct, at 1-week low
* Miners hit by weak China data
* Johnson Matthey, SABMiller up after results
By Toni Vorobyova
LONDON, Nov 21 (Reuters) - The FTSE 100 edged down to one-week lows on Thursday as concerns about the scaling back of U.S. Federal Reserve stimulus in coming months outweighed a crop of solid earning reports from British blue chips.
Fed minutes, released after the European markets closed on Wednesday, showed that officials could decide to reduce bond purchases at one of their next meetings, thus depriving global equity markets of a key upward catalyst.
"Our house view is that there is 25 percent chance in December, 25 percent in January and 50 percent in March," said Nick Xanders, who heads up European equity strategy at BTIG.
News of slowing factory growth in top metals consumer China also weighed on Britain's miners-heavy bourse.
The FTSE 100 was down 31.80 points, or 0.5 percent, at 6,649.28 points by 0813 GMT. However, it managed to outperform its European rivals thanks to some cheer from the earnings season.
"The UK is growing better and will probably continue to do so," said Xanders at BTIG. "I think they will continue to outperform."
Johnson Matthey led the FTSE 100 gainers, up 2.0 percent after the world's largest maker of catalysts to control car emissions, posted a 13 percent rise in first-half profit, helped by increased global production of cars and trucks and demand for its speciality catalysts.
Results also lifted brewer SABMiller, which added 0.7 percent.
"Despite lackluster volume trends (plus 2 percent), it is encouraging to see the margin expansion and pricing trends in the company's key growth markets of LatAm, Africa, and Asia Pacific," analysts at Liberum Capital said in a note.