An employment agency that supplied Sports Direct staff in Derbyshire has lost its appeal against a six-figure pay-out for underpaying workers.
Best Connection Group Ltd was fined £263,000 in 2016 and was told to pay £470,000 to workers to whom it had paid less than the national minimum wage.
A tribunal heard it sent up to 2,000 staff a week to Sports Direct's warehouse in Shirebrook, Derbyshire.
Judge Sarah Goodman said the agency did not dispute the underpayment.
In January last year, HM Revenue and Customs (HMRC) began an investigation into conditions at the warehouse.
It found some workers had been docked a quarter of an hour's pay if they clocked on one minute late, and also had to queue for an average of 11 minutes for security checks after their shifts had finished.
A committee of MPs said some staff at the site were treated "as commodities rather than human beings".
Best Connection had claimed it was the victim of a "deliberate ploy" by HMRC to extract more money from it and claimed the penalty was designed to be "punitive" and a "deterrent".
'Dodge its responsibilities'
It also said HMRC's notices were invalid because they did not name individual workers or the amount by which they had been underpaid.
However, Ms Goodman rejected all of the complaints and confirmed the penalty.
The agency only had to pay £131,814 - half of the 2016 fine - because it paid within 14 days, meaning the company paid out more than £600,000 in total.
Luke Primarolo, regional officer for the union Unite, said: "It is shameful that Best Connection has gone to these lengths to dodge its responsibilities and avoid paying up the money it owes to workers it has short changed and exploited.
"No one is above the law and workers will welcome this judgment. They will now expect swift payment of the money they are owed."