Share prices ended lower on London's Stock Exchange Thursday, as the resignation of Soviet Foreign Minister Eduard Shevardnadze created uncertainty in the financial markets. The resignation ``does add to the general economic uncertainty which makes markets nervous,'' said John Reynolds, equity strategist at the London brokerage firm County Natwest Woodmac. Wall Street also was having its share of jitters over the news. Throughout most of the European afternoon, the Dow Jones industrial average was under pressure, although by the close of the session in London, Wall Street appeared to be reversing its losses. The Financial Times-Stock Exchange 100-share index was down 19.9 points, or 0.9 percent, at 2,158.8 at the close. The Financial Times 30-share index fell 19.9 points to close at 1,687.2. The Financial Times 500-share index fell 9.79 points to close a 1,143.22. Volume was 590.2 million shares compared with 509.3 million shares Wednesday.