Britain's leading share index was 0.4 percent weaker in mid-session trade on Tuesday, with weakness in commodity stocks outweighing gains in financials as investors booked profit after recent gains.
By 1146 GMT the FTSE 100 .FTSE was 20.91 points lower at 5144.79, after closing 83.50 points higher on Monday at 5,165.70.
However the FTSE was still up 16.3 percent this year, having soared 49 percent since touching a six-year trough in March.
Energy and mining stocks dragged the index lower as economic uncertainty weighed on investor sentiment on the demand outlook for raw materials.
BP (BP.L), Royal Dutch Shell (RDSa.L), BG Group (BG.L), and Tullow Oil (TLW.L) dropped 0.1-1.4 percent.
Miners were weighed by weaker metal prices. Rio Tinto (RIO.L), Xstrata (XTA.L), Lonmin (LMI.L), Anglo American (AAL.L) and Kazakhmys (KAZ.L) were down 1 percent to 3.2 percent.
There's a degree of profit taking with many investors quick to cash in after yesterday's gains, but the underlying market sentiment remains positive, said Howard Wheeldon, strategist at BGC Partners. It leaves us asking the question of if, not when, the correction is coming.
A mixed bag of data also helped keep the FTSE in the red after figures showed a sharp widening in Britain's current account deficit and a decline in consumer credit but a surprise increase in mortgage lending. ECONGB
Meanwhile, retail sales rose unexpectedly in September and stores were optimistic sales would continue to grow in October, industry data showed.
Across the Atlantic, stock index futures fell ahead of September U.S. consumer confidence numbers due later together with the July Case/Shiller house prices report.
Futures for Dow Jones industrial average DJc1, the S&P 500 SPc1 and the Nasdaq Composite NDc1 were off 0.1-0.5 percent.
Property stocks were the heaviest losers among British blue chips, with Hammerson (HMSO.L) and Land Securities (LAND.L) falling 2.1 and 2.9 percent respectively after Credit Suisse cut the sector to 'benchmark' from 'overweight'.
Financials were the strongest performers with banks mostly higher after French bank BNP Paribas (BNPP.PA) joined a recent European rush to repay government aid from the credit crisis by launching a 4.3 billion euro ($6.3 billion) capital increase.
Barclays (BARC.L), Standard Chartered (STAN.L), Royal Bank of Scotland (RBS.L) and Lloyds Banking Group (LLOY.L) added 1.2-2.7 percent, but HSBC (HSBA.L) retreated slightly.
Life insurers were in demand, with investors buoyed by takeover talk.
Legal & General (LGEN.L) climbed 4.6 percent, building on a 5.2 percent rise on Monday, on more bid talk following a weekend report it has prepared a defence document against a potential bid from takeover vehicle Resolution (RSL.L).
The speculation saw Aviva (AV.L), Standard Life (SL.L), Prudential (PRU.L) and Old Mutual (OML.L) add 0.7-2.7 percent. Friends Provident (FP.L), also a target for Resolution, dropped 0.2 percent.
Compass (CPG.L) was among the top gainers, up 2.6 percent after the world's biggest caterer said it expected to increase full-year earnings per share by 14 percent as new business wins, cost cuts and a weak British pound helped maintain growth.