Shares in the main listed UK housebuilders dropped by as much as 5% after broker Jefferies warned that economic and political uncertainty had clouded the outlook for mortgage approvals and housing transactions.
The FTSE 100 Index was 68.8 points lower at 6501.1, as Brent crude fell below $50 a barrel.
In currencies, sterling was about 0.4% higher against the dollar, at $1.52. The pound was marginally stronger against the euro, at €1.28.
Meanwhile, the biggest risers in the FTSE 100 index yesterday were ITV up 4p at 213.5p, Friends Life up 6.6p at 371.7p, Aviva up 7.2p at 490.4p, and John Matthey up 50p at 3506p.
The biggest fallers on the index were Taylor Wimpey which was down 7.1p at 125.7p, Persimmon down 80p at 1459p, Barratt Developments down 23.3p at 431.4p, and Morrisons down 8.4p at 176.3p.