UPDATE 2-Financials, miners lead FTSE 100 rebound, but Burberry, Thomas Cook slip

* FTSE 100, FTSE 250 up 0.8%

* Banks, miners boost main index

* Burberry slumps after FY report

* Profit warning takes Thomas Cook to multi-year low

* Genetics co Genus jumps after licensing deal

* Sophos surges on better-than-expected profit (Adds analyst comment, company news items, updates to closing prices)

By Muvija M and Yadarisa Shabong

May 16 (Reuters) - Rallying banks and mining stocks lifted Britain's FTSE 100 on Thursday, but weak earnings hit luxury brand Burberry and Thomas Cook was floored by a profit warning.

The main index bounced 0.8%, gaining for the third consecutive session, and the mid-caps gained by the same margin, helped by strong earnings reports.

UK shares, along with their European counterparts, reversed initial losses after a strong open on Wall Street, which was lifted by earnings and strong economic data, despite U.S. curbs on China's Huawei heigtening trade tensions.

Miners jumped nearly 2%, continuing a three-day winning streak, as iron ore futures scaled a record high on strong demand, while aluminum prices also rose as production shutdowns at one of China's biggest smelters fueled supply worries.

Private equity firm 3i advanced 3.2% after reporting a jump in total returns.

Exporters were also lifted after the pound neared a four-month low as Britain's Prime Minister Theresa May fought to keep her Brexit deal intact, amid growing fears of a disorderly departure from the European Union.

However, Burberry slumped 5.9% on its worst day since January after reporting a drop in adjusted operating profit.

National Grid slipped 3.4% - its biggest one-day drop this year - after reporting a drop in earnings and the opposition Labour Party announced plans to take energy networks back into state ownership if elected.

On the FTSE small-cap index, Thomas Cook slumped more than 14.7%, after earlier hitting a more than 6-1/2-year low, as the travel group said economic and political uncertainty would hit its profit this summer.

Its larger rival TUI fell 2.5%, while easyJet slipped 2.1% and IAG gave up 1.2%.

The midcap index drew some strong news-related moves.

Livestock genetics firm Genus jumped 14.1% after a deal to license its know-how on virus-resistant pigs to Beijing Capital Agribusiness, which will seek regulatory approval for the pigs in the world's biggest pork market.

Cyber security firm Sophos surged 14% on its best day in more than a year after reporting higher-than-expected annual earnings, while Premier Oil jumped 8.8% as it hiked its production target.

Metro Bank slumped 8.1% after the Financial Times reported that its share placing might be priced at a 10% discount. After the market close Metro Bank announced plans to raise 350 million pounds at a price of 500 pence per share, a 7.3% discount to Thursday's closing price. (Reporting by Muvija M and Shashwat Awasthi in Bengaluru; editing by Larry King and Alexander Smith)