REUTERS/Toby Melville London Stock Exchange open hit by one hour delay on Thursday. Prices for stocks listed on the FTSE 100, Britain's benchmark share index, were unavailable immediately after the 8 a.m. open. LONDON — Trading on Europe's largest stock exchange, the London Stock Exchange, was delayed by an hour on Thursday after an unidentified glitch prevented the venue from beginning business on time. It is currently unknown what caused the glitch that prevented the exchange's opening auction, the key mechanism for the start of trade, from taking place just before its scheduled start time at 8.00 a.m.