DWF has clinched a victory for supermarket giant Morrisons in a U.K. Supreme Court appeal relating to a class action brought by over 9,000 of the retailer's employees.

On Monday, judges ruled that the supermarket giant was not "vicarious liable" for the actions of an internal auditor who was alleged to have leaked the payroll data of around 126,000 employees as part of an "irrational grudge" against the retailer. 

The decision was a reversal of the judgement by the Court of Appeal which ruled that Morrisons was liable for the auditor's actions. 

In July 2015, it was widely reported that the auditor was jailed for eight years after being convicted at Bradford Crown Court of fraud, including securing unauthorised access to computer material and disclosing data. 

DWF acted for WM Morrison Supermarkets, which instructed Blackstone Chambers and 11KBW in the case. Consultant Andrew Harris led the DWF team. 

The firm said in a statement: "We are delighted to report that our client Morrisons has been successful in the landmark case in the Supreme Court concerning the criminal data breach committed by an employee which saw the personal data of employees put onto the internet."

Employment lawyer Kirsty Rogers commented: "The Court had already found that Morrisons had no fault-based liability and the Supreme Court has now ruled that Morrisons also has no no-fault vicarious liability for the malicious actions of its employee."

Law firm JMW acted for the former employees in the case, led by partner Nick McAleenan.

In a statement, McAleenan commented on the ruling: "My clients entrusted their personal information to their employer, Morrisons, in good faith. When their information was subsequently uploaded to the internet by a fellow employee, it caused an enormous amount of upset and distress to tens of thousands of people.

"The Supreme Court's decision now places my clients, the backbone of Morrisons' business, in the position of having no legal avenue remaining to challenge what happened to them."