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Aug 16 (Reuters) - A technical glitch delayed the start of trading on Friday on the UK blue chip FTSE 100 and midcap stock indexes in what was the longest outage at one of the world's top bourses in eight years.
The London Stock Exchange was investigating a "potential trading services issue" and would have further information by 0815 GMT, it said in a statement on its website.
An LSE spokeswoman said a "technical issue had affected trading in some securities," but she had no further detail on the cause of the fault or when the problem might be resolved.
The outage was affecting hundreds of shares in some of the UK's largest companies, including Shell, Unilever and HSBC and BHP Group, worth a total of $2.8 trillion.
This is the second outage at the LSE, which handles about 5 billion pounds ($6.1 billion) worth of volume each day, in just over a year.
In June 2018, the opening auction was delayed due to a technical fault, but trading resumed after an hour.
Prior to that, the market was shut until lunchtime one day in February 2011.
Reuters News' parent Thomson Reuters holds a 45% stake in financial data and news provider Refinitiv, which is being bought out by the LSE. Thomson Reuters will own 15% in LSE after the proposed deal closes. ($1 = 0.8253 pounds) (Reporting by Shashwat Awasthi in Bengaluru, Thyagaraju Adinarayan and Josephine Mason in London editing by Jason Neely and Keith Weir)