(For a Reuters live blog on U.S., UK and European stock markets, click LIVE/ or type LIVE/ in a news window) * FTSE 100 down 0.1%, FTSE 250 flat Aug 12 (Reuters) - London’s FTSE 100 eased on Thursday as weakness in heavyweight energy stocks outweighed optimism over a slew of strong corporate earnings reports. The blue-chip FTSE 100 edged 0.1% lower with oil majors BP and Royal Dutch Shell being the top drags. Insurer Aviva rose 3.5% and was the top gainer on the FTSE 100 after it reported a 17% rise in first-half operating profit and said it would return at least 4 billion pounds ($5.55 billion) to shareholders. Britain’s economy grew by a faster-than expected 1.0% in June, boosted by the huge services sector, against a Reuters poll of economists that pointed to a monthly growth of 0.8%. The domestically focussed mid-cap index was flat with Cineworld leading gains on its U.S. listing plans, countering losses in financials. (Reporting by Shashank Nayar in Bengaluru; Editing by Subhranshu Sahu)