1130 GMT - The uptick in buyer appetite for U.K. public companies is proof that London-listed stocks are undervalued, Panmure Liberum's Joachim Klement and Francisca Reis write. "If investors need convincing that the U.K. stock market is undervalued, all they have to do is look at M&A activity," the analysts say. Mergers and acquisitions completed or pending so far this year are worth close to 58 billion pounds--a two-decade record, if mega-mergers are removed, they say. Segro and Schroders are among blue-chip U.K. companies to attract takeover offers so far this year at a significant premium to stock market valuation. The volume shows that private equity buyers and rival companies believe U.K. stocks are trading at a discount, they add.