* FTSE 100 up 0.2%, FTSE 250 flat

July 23 (Reuters) - London's FTSE 100 rose on Thursday as a slate of upbeat quarterly earnings reports bolstered optimism about a post-pandemic corporate rebound, with Unilever surging after reporting a much lower drop in sales than feared.

The Anglo-Dutch maker of Dove soaps and Knorr soups jumped 6.8% to the top of the FTSE 100 as it said a strong performance in North America helped offset the hit from coronavirus lockdowns.

The blue-chip FTSE 100 was up 0.2%, with the world's biggest advertising firm, WPP, also among the top gainers after a strong quarterly showing by French rival Publicis Groupe SA.

The mid-cap FTSE 250 was flat with gains in consumer staples, materials and energy stocks offset by declines for financials and real estate firms.

Security contractor G4S rose 4.3% to the top of the FTSE 250 after reporting a higher-than-expected first-half operating profit. (Reporting by Sagarika Jaisinghani in Bengaluru; Editing by Shounak Dasgupta)