The FTSE 100 Index fell 34.5 points to 6054, heading for its seventh day of losses and closing in on a three-month low.
Sports Direct International was one of the biggest fallers in the top flight, slumping 16p to 576.5p, in a week that has also seen the firm mired in controversy surrounding its treatment of staff.
With Brent Crude below $40 a barrel (£26), oil stocks were lower. Royal Dutch Shell fell 28.5p to 1505p, while BP was 3.9p lower at 347.2p.
Miner Glencore rose 0.2p to 89.1p, as it continued to find favour off the back of earlier well-received debt reduction plans.
Other miners also lifted after a sector sell-off earlier in the week, with Fresnillo up 7p to 680p and Antofagasta rising 1p to 447p.