* FTSE 100 down 0.6 pct
* FTSE 250 down 0.3 pct
* HSBC drags on main index as earnings disappoint
* Baker Greggs jumps to life high
* Plus500 falls for 7th straight day
* Indivior slips on U.S. Supreme Court ruling (Adds news items, updates to closing prices)By Shashwat Awasthi and Muvija MFeb 19 (Reuters) - Britain's main index fell on Tuesday,weighed down by disappointing results from blue-chip heavyweightHSBC and a stronger pound, while mid-cap baker Greggs surged toa record high after guiding to higher full-year profits.The FTSE 100 closed down 0.6 percent, its biggestfall in nearly two weeks, and the FTSE 250 was down 0.3percent.HSBC was the biggest drag on the main bourse on itsworst day in almost two years, as uncertainty around theChina-U.S. trade situation was reflected in the Asia-focusedbank's disappointing profit growth. Its shares slipped 4 percent, knocking more than 20 pointsoff the FTSE 100 and dragging peer Standard Chartered down 2.1 percent, with the bank warning weaker economic outlooksfor China and Britain would pose more challenges this year.Spreadex analyst Connor Campbell said HSBC finds itself"stuck in the middle of a Venn diagram covering China's slowingeconomy, the concerns surrounding global trade and Britain'sBrexit mess."Sterling rose on hopes that Prime Minister Theresa May'sBrexit talks in Brussels this week would yield progress, whilerelatively strong labour market data helped sentiment towardsthe currency. Reckitt Benckiser fell 2.3 percent while other majordollar earners including AstraZeneca and Unilever also gave up a percent each.A new round of China-U.S. trade negotiations kicks off thisweek and reports of progress in the talks, despite a lack ofclear details, have raised hopes that the countries can reach acompromise by a March 1 deadline. High street baker Greggs jumped 11.2 percent to anall-time high on the mid-cap index as sales rose in the firstseven weeks of 2019 and it forecast higher full-year underlyingpretax profit. But Indivior tumbled 11 percent after the U.S.Supreme Court rejected the drugmaker's bid to block Dr. Reddy'sLaboratories' copycat of its lucrative opioidaddiction treatment Suboxone Film. Online trading platform Plus500 , which has slumpedsince last week after a profit warning and a drafting error inits 2017 report, fell for a seventh straight session. The stockwas down 10.7 percent.Engineering firm Cobham advanced 4.9 percent afteragreeing to settle a dispute with Boeing over its delayedKC-46 aerial refuelling programme. (Reporting by Shashwat Awasthi and Muvija M in Bengaluru;Editing by Janet Lawrence)