The main index moved further away from a near four-month high it hit earlier this week and gave up 0.5pc, as trade-sensitive stocks such as Asia-focussed HSBC and miners weighed.
Bucking the trend, Ocado jumped 11pc and was on track for its best day since May 2018, after signing a technology partnership with Japan's biggest supermarket operator, Aeon Co Ltd.
The FTSE 250 snapped a five-day winning streak as it shed 0.3pc by 0838 GMT, but still hovered close to a near 1-1/2 year high. The index is on course for its third straight month of gains and the biggest since January.
St. James's Place was the biggest blue-chip loser, falling 5pc after Goldman Sachs downgraded the stock and raised concerns about the wealth manager's future dividend growth.
Shares of several domestically focussed firms declined after a survey showed British consumer confidence reeling at its joint-lowest level since November 2013.
Confidence was subdued as uncertainty around the Dec. 12 general election and Brexit still lingers. Housebuilders were the worst hit, Persimmon and Berkeley lost 1.5pc each, and mid-cap Bellway shed 2pc.
Trading volumes were once again low with Wall Street set to return to a half-day session after Thanksgiving, and Beijing's warning of counter measures after the Hong Kong legislation was enough for risky assets to fall out of favour.
However, OANDA analyst Jeffrey Halley said, given China's issues around corporate debt and regional bank credit quality, the country could ill-afford to waste any progress made on trade talks.
Among small-caps, Reach soared 12pc, on course for its best day since August 2015, after the Daily Mirror publisher said it was confident of meeting annual targets.
Redde climbed 5.5pc higher to 114.6 pence after peer Northgate agreed to buy the support services group in a 128.4 pence a share deal. Northgate shares slipped 3pc.