The London Stock Exchange opened successfully this morning after being hit late yesterday by a connectivity problem with its Infolect information-broadcast system that prevented some trades being closed.

The outage hit shortly before close of trading and forced the exchange to extend its closing auction by a hour and a half, from 4.30pm until 6pm. Even so it was reported that that some traders left for the day with trades unexecuted.

The glitch is the first to hit the LSE for seven years and particularly badly timed since it comes only days after the introduction of the Markets in Financial Instruments Directive, which has opened up trading competition beyond traditional exchanges. New entrants offering trading platforms include Project Turquoise, backed by nine investment banks.

A spokesperson said the exchange’s much vaunted core TradElect platform had not faltered at any point. It went live in June, marking the culmination of a four-year technology overhaul at the exchange, and has only just been upgraded to boost processing speed by 40% and systems capacity by 70%.

She said the problem appeared to lie with Infolect’s three interactive gateways, which send out about 10 million separate pieces of market information daily, including share prices, to about 100,000 terminals.

Infolect was launched two years ago in place of the exchange’s London Market Information Link platform. It uses Microsoft .net technology and a SQL Server database, and runs on more than 100 Intel-based 32-bit Proliant servers. It its accessed by most of the exchange’s member organisations via Extranex, its privately managed IP network.