Britain's FTSE 100 dipped after rising for four days as several blue-chip stocks traded ex-dividend, while NMC Health plus insurers Aviva and Admiral slipped after earnings reports, but Melrose gained after its adjusted profit nearly tripled.

The FTSE 100 was down 0.5 percent and the FTSE 250  was down 0.7 percent by 0945 GMT.

Miners Rio Rinto, BHP and Evraz plus house-builder Persimmon all traded ex-dividend and were among the top drags on the main bourse.

United Arab Emirates' healthcare provider NMC Health slipped 6.4 percent on course for its worst day since July 2016 after posting annual results.

Jefferies analysts said NMC's adjusted earnings per share were lower than their consensus as financial charges were much higher than expected.

Insurer Admiral Group shed 4.6 percent to be on course for its worst one-day fall in more than a year and a half. Though the company reported better-than-expected 2018 earnings, a trader said that was largely on benefits related to Ogden rates.

Fellow underwriter Aviva and asset manager Schroders  also fell 3.2 percent and 3.4 percent respectively after their annual earnings reports.

But turnaround specialist Melrose Industries gained 4 percent to its highest level since November after its full-year adjusted pretax profit nearly tripled, boosted by last year's hostile takeover of British engineer GKN.

Also outperforming was event manager and publisher Informa  which rose 2.1 pct as its organic revenue topped market view.

"With some big names ... going ex-dividend, and the general mood dour, the FTSE didn't stand a chance," said Spreadex analyst Connor Campbell.

Further muddying sentiment, EU officials said on Wednesday that talks with Britain on amending its divorce deal with the European Union had made no headway and no swift solution was in sight.

Small-cap real estate agent Countrywide tumbled 11 percent as it forecast flat full-year earnings, citing more market weakness surrounding Britain's exit from the European Union.

Vietnam Enterprise Investments slumped 5.8 percent to the bottom of the mid-cap index after APG Funds dissolved their stake in the company.

But defence contractor Ultra Electronics jumped 8 percent after a rating upgrade from JP Morgan, extending gains from a day earlier when it reported results.

Alfa Financial Software Holdings surged over 20 percent and was on course for its best-ever day after 2018 report showed a strong recovery in the second half.