DIY store B&Q and the fast food chain Five Guys are among hundreds of UK businesses named by the government for paying staff below the minimum wage.
More than 600 employers were ordered to pay affected workers the outstanding wages, with £4m returned to workers, according to the Department for Business and Trade.
The firms have also been issued penalties worth £7m.
B&Q said the underpayments were unintentional and the result of calculations involving geographical allowances, while Five Guys blamed "technical differences in how payroll regulations were applied".
The list of 658 businesses includes shops, restaurants, nurseries, social care providers and a handful of NHS trusts. The government did not say over what time period the underpayments spanned.
Minimum wage is £12.71 for staff aged 21 and over. For 18 to 20 year olds the rate is £10.85, and for under 18s and apprentices it is £8.
B&Q underpaid 4,530 workers a total of more than £456,000, according to the government.
B&Q said in response: "The shortfalls in payments were unintentional. They relate to calculations involving geographical allowances which are paid in addition to minimum hourly rates. All affected colleagues were quickly paid in full in July 2025."
Five Guys, named in the list as owing over £54,000 to 3,699 staff, said "technical differences in how payroll regulations were applied" led to its underpayments, which were identified in a review by the HMRC, the UK's revenue and tax authority.
"We worked closely and transparently with HMRC throughout the process and have made all required payments to affected current and former employees," the company said.
St George's, Epsom and St Helier Hospital Group failed to pay over £123,000 to 75 workers, according to the list, which also says St George's University Hospitals in Wandsworth, London, underpaid 55 workers.
A spokesman for the two hospital trusts said that "no colleagues were underpaid".
"This relates to a technical compliance issue where part of their salary for a non tax-deductable 'salary sacrifice' (for example, towards childcare) was not counted towards the national minimum wage, even though their gross salary was above the national minimum wage," he said.
A spokesperson said apprentices at Norfolk Community Health and Care NHS Trust were inadvertently underpaid between 2019 and 2023.
They said while their pay met the requirements for their contracted hours, meetings, handovers and time spent changing into uniform hadn't been accounted for, adding the trust has since changed policies and practices.
The other trust named has been contacted for comment.
There were also several nursing homes on the list, and multiple childcare providers.
Business Secretary Jonathan Reynolds said the government was determined to stamp out the practice of "short-changing your staff".
"The best businesses know that looking after your workers isn't just the right thing to do, it's the smart thing to do," he said.
Kate Dearden, minister for the future of work, said: "Underpaying your staff is illegal, and we will not let workers foot the bill for their boss failing to follow the rules."
"Every employer should check their payroll now and reach out to Acas if they need further support," she added.
The first 10 employers on the government's list, which was sorted by the amount of wages not paid, are:
1. B&Q Ltd, failed to pay £456,934.72 to 4,530 workers.
2. Elysium Healthcare Holdings 3 Ltd, Borehamwood, failed to pay £330,048.81 to 1,095 workers.
3. St George's, Epsom and St Helier Hospital Group, failed to pay £123,331.97 to 75 workers.
4. Support Staff Services Limited, Slough, failed to pay £119,715.13 to 323 workers.
5. Forest Holidays Ltd, Moira, failed to pay £100,308.68 to 598 workers.
6. St George's University Hospitals NHS Foundation Trust, London (Wandsworth), failed to pay £77,498.91 to 55 workers.
7. Lanes Group Limited, Leeds, failed to pay £67,893.34 to 297 workers.
8. UK Care Team Ltd, Leicester, LE19, failed to pay £67,082.76 to 99 workers.
9. Five Guys JV Limited, London (Royal Borough of Kensington and Chelsea), failed to pay £54,642.47 to 3,699 workers.
10. Merlin Cinemas Limited, Redruth, failed to pay £50,198.75 to 181 workers.
The list marks the first "naming round" since the Fair Work Agency was set up in April under the Employment Rights Act.
As well as enforing the minimum wage, the agency also will soon tackle practices of denying workers holiday and sick pay.
Chair of the agency's advisory board, Matthew Taylor, said naming employers which underpay staff was an important reminder that "paying the minimum wage is not optional - it is the law".
He said: "Most employers want to do the right thing, and we will support them to comply, but those who fall short should expect robust enforcement to protect workers and maintain a fair playing field for responsible businesses."
