Trading on the London Stock Exchange (LSE) was delayed by an hour and 40 minutes today, with a software error blamed for the outage.
Trading started at 09:40 after the incident was resolved.
The LSE outage was the longest in eight years.
It’s the third major infrastructure outage in Britain in a week, following an IT outage at British Airways that left tens of thousands of passengers stranded, and the major power cuts that left commuters in the dark on the underground.
Trading on the lesser AIM market continued.
The LSE said in an emailed comment: “London Stock Exchange experienced a technical software issue this morning that affected trading in certain securities, including FTSE 100 and FTSE 250 stocks. Following resolution of the issue regular trading in all securities commenced at 09.40.”