The government said on Wednesday that 202 businesses – ranging from major high-street names to small businesses and sole traders – had broken the law by leaving around 63,000 workers out of pocket.
The companies paid a combined £7 million (€8.19 million) in arrears and fines for the breaches, the statement released by the government's department for business and trade said.
"Paying the legal minimum wage is non-negotiable, and all businesses, whatever their size, should know better than to short-change hard-working staff," Kevin Hollinrake, a minister in the department, said.
"Most businesses do the right thing and look after their employees, but we're sending a clear message to the minority who ignore the law – pay your staff properly or you'll face the consequences," Hollinrake added.
WH Smith, a mainstay at Britain's airports and train stations, headed the list, having failed to pay £1 million (€1.17 million) to 17,607 workers. M&S failed to pay £578,391 (€676,350) to 5,363 workers, while Sainsbury's-owned Argos did not pay £480,094 (€561,410) to 10,399 employees, the statement said.
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A spokesperson for M&S said the company was only named because of an unintentional technical issue from over four years ago, adding it was remedied as soon as it became aware of the issue.
"Our minimum hourly pay has never been below the national minimum wage – it is currently above it – and no colleagues were ever underpaid because of this," the spokesperson added. The minimum wage in Britain went up by 9.7% to £10.42 (€12.18) per hour in April.
The government noted in its statement that not all minimum wage underpayments were intentional, but added there was no excuse for underpaying workers.
A Sainsbury's spokesperson said that a payroll error was identified in 2018, which affected some Argos store workers and drivers and dated back to 2012 – before its acquisition of Argos.
The spokesperson added that it was rectified, and that the Argos worker hourly rate was now aligned with Sainsbury's.
In its response, WH Smith said it had misinterpreted how the statutory wage regulations were applied to its uniform policy for staff working in its stores. "This was a genuine error and it was rectified immediately with all colleagues reimbursed in 2019," the company said.