LONDON (Dow Jones)--London Security PLC (LSC.LN) said Monday it purchased 10,000 ordinary shares of 1 pence each for cancellation at a price of 900 pence per share. -Shares at 1517 GMT unchanged at 862.5 pence. By Iain Packham, Dow Jones Newswires; 44-20-7842-9269; [email protected] (END) Dow Jones Newswires July 19, 2010 11:18 ET (15:18 GMT)