Trading on the London Stock Exchange (LSE) returned to normal on Thursday following a technical hitch with the Infolect system during Wednesday afternoon.
Its closing auction, which normally takes about ten minutes and starts at 16:30 BST, was extended to 18:00 BST because screens had frozen at 15:50 BST.
It was the first technical breakdown for seven years and the Business Times reported that some stockbrokers said it had come at an unfortunate time when the numbers of exchanges had increased.
A broker told the website: "This is embarrassing for the LSE because the volumes will go to other exchanges."
The LSE statement said that the technical problem had affected the full participation of member firms during trading and the end of day auction.
"The cause of the technical problem has been identified and a solution implemented," the statement read.
It went on to say that as the biggest equity market in Europe it made every effort to deliver a first-class service.
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