The London Stock Exchange says human error, possibly in "suspicious circumstances" was at fault for an outage on its Turquoise trading platform this morning, raising the spectre of foul play.
In an update posted on its Web site at 08.57 the LSE informed users: "Turquoise is currently experiencing a networking related issue which has impacted all participants. An timeframe for resolution is not yet available."
Customers were being advised to disconnect all applications to prevent order submission before trading resumed at about 10.30am.
This afternoon the firm has blamed human error, adding: "Preliminary investigations indicate that this human error may have occurred in suspicious circumstances. The LSEG take this matter very seriously and a full internal investigation has now begun. The relevant authorities have been informed."
In addition, the group says the incident, along with necessary network upgrades means that the migration of Sets to a new technology platform will now not take place until early next year.
Turquoise migrated to the MillenniumIT system, a Sri Lanka-based vendor recently acquired by the LSE, at the beginning of last month. The main market was initially set to follow yesterday but had already been delayed before today's developments.