A computer systems failure knocked out the exchange, following frantic early-morning trading.
A technical "meltdown" caused the London Stock Exchange (LSE) to be suspended this morning.
It is thought that computers at the exchange failed due to the high volume of trades which were being processed this morning, as investors reacted to the US government's bailout of mortgage lenders Fannie Mae and Freddie Mac. As a result the LSE's flagship FTSE 100 index rose by four percent to 5,440 this morning, before being suspended at around 09:15 BST.
A spokesperson for the LSE said subsequently that technical staff were "preparing" to re-instate networks in a "controlled way", before the exchange was partially restored at 11:45 BST. However, traders are only currently allowed to enter or delete share trades, rather than execute them.
This morning's outage is the worst to hit the exchange for eight years.
Speaking to Bloomberg, Sejal Patel, a London-based trader at CMC Markets, suggested that the computer crash pointed to the apparently antiquated nature of the current exchange system. "Today's meltdown from the LSE couldn't have come at a worse time," he commented. "It has served to highlight the benefits of having an additional exchange [in London]."
Elsewhere, the global stock exchanges have also enjoyed bumper days of trading thanks to the rescue of Fannie and Freddie. Hong Kong's Hang Seng has gained around 4.3 percent, while Frankfurt's DAX is up 3.4 percent as of 13:00 BST.
