THOUSANDS of employees at Morrisons are due compensation for the “upset and distress” caused by a huge data breach after a landmark High Court ruling yesterday.

The supermarket chain had denied liability in the case brought by current and former staff.

Disgruntled former employee Andrew Skelton stole data which included the salary and bank details of nearly 100,000 staff.

The security breach occurred in 2014 when Mr Skelton, a senior internal auditor at the retailer’s Bradford headquarters, leaked the payroll data.

He posted names, addresses, bank account details and salaries online and sent it to newspapers.

Over 5,500 workers brought the claim against the company, while the ruling could open the door for the other 94,000 people affected to bring a compensation claim, lawyers said.

In 2015, Mr Skelton was found guilty of fraud, after securing unauthorised access to computer material and disclosing personal data, and was jailed for eight years.

His motive appeared to have been a grudge following accusations he had been dealing legal highs at work.

Judge Mr Justice Langstaff ruled that Morrisons was vicariously liable, as primary liability had not been established.

JMW solicitor Nick McAleenan, acting for the 5,518 former and current staff, said: “The High Court has ruled that Morrisons was legally responsible for the data leak.

“We welcome the judgement and believe that it is a landmark decision, being the first data leak class action in the UK."

Jonathan Barnes, counsel for the claimants, told Mr Justice Langstaff in October that Morrisons had already been awarded £170,000 compensation against Mr Skelton.