DLA Piper is the largest law firm in the world by revenue, posting £1.5 billion last year. The firm has more than 1,000 partners, of which around 450 are equity partners.

Peter Wright, chair of the Law Society’s Technology and Law Reference Group and managing director of DigitalLawUK, said that if safeguards were not in place to protect a firm of DLA’s magnitude then the question is who does?

Detailing the kind of content which could be compromised in an attack, Mr Wright said: “For a law firm there are obvious risks, there could be a client database or an archived database that is not as secure as first thought. Further, confidential client emails are likely to be on a firm’s systems.”

A DLA Piper spokesperson said: “On June 27, 2017, our advanced-warning system detected suspicious activity on our network, which, based on our investigation to date, appears to be related to the global cyber event known as “Petya”. Our IT team acted quickly to prevent the spread of the suspected malware and to protect our systems.

“We immediately began our investigation and remediation efforts, working closely with leading external forensic experts and relevant authorities, including the FBI and UK National Crime Agency. We are working to bring our systems safely back online.”