City of London traders hit by Russia-linked cyber attack

Trading in the City of London has been plunged into chaos after a Russian-linked ransomware gang attacked a company that plays a key role in Britain’s financial system.

Lockbit, the group behind the cyber attack against Royal Mail last month, targeted trading software provider Ion Group on Tuesday.

The London-based company plays an integral role in the plumbing that underpins the trading of shares, debt and derivatives in the Square Mile and around the world.

Ion said 42 clients have been affected by the attack as it faces disruption in its cleared derivatives division.

One senior City banker described the attack as a “major incident” that “would take out most of the City if it were to escalate”.

It is understood that some clients could not contact Ion by phone on Tuesday, forcing some to physically travel to the company’s office at St Paul’s to seek answers about the attack.

The attack has also had a knock-on effect on other trade processing systems and has forced some companies to process trades manually.

In a statement on its website, Ion said: “The incident is contained to a specific environment, all the affected servers are disconnected, and remediation of services is ongoing.”

The attack comes just weeks after Lockbit forced Royal Mail to suspend international postal deliveries leaving more than half a million parcels and letters stuck in limbo.