The FTSE 100 was down 0.2 percent. The FTSE 250  added 0.3 percent by 0740 GMT.

Mining shares slipped as a decline in copper prices on fears of a global economic slowdown more than offset progress in trade talks between the United States and China, the world's largest copper consumer.

The European Union on Thursday granted Britain a six-month extension to leave the bloc, averting a disorderly exit on Friday and giving Prime Minister Theresa May more time to break the Brexit deadlock at home.

The extension, coupled with data showing British house prices improved in March for the first time since July, buoyed housebuilders. Persimmon and Berkeley rose more than 1 percent.

The Brexit delay also helped airline stocks. EasyJet gained 4.4 percent and IAG 3.4 percent.

But general insurers Standard Life Aberdeen and Aviva gave up 5.4 percent and 4.1 percent respectively and were among the biggest drags on the blue-chip index as the stocks traded ex-dividend.

Precious metals mining company Fresnillo shed 2 percent after its quarterly production fell, though it stuck to output targets for the year.

Luxury brand Burberry added 1.5 percent and outperformed the main index French peer LVMH reported results that beat forecasts.

Drugmaker Indivior, which was mauled in the previous session after a U.S. Justice Department indictment, recovered 7.3 percent.