Labour leader Ed Miliband is to slam Newcastle United chairman Mike Ashley in his next speech, claiming that the Sports Direct owner uses "Victorian practices" in his discount brand sports stores.
It comes as the Doncaster North MP attempts to stamp his authority on his party following reports that some members had concerns about his leadership qualities.
He is set to discuss plans to change the law if Labour win the next general election and will be particularly critical of Sports Direct's treatment of their employees.
"Sports Direct has thousands of its employers on zero-hours contracts, the vast majority of its workforce," he will say, according to The Chronicle. "Sports Direct has predictable turnover, it is a modern company with stores on many high streets and, judging by its success, where many people shop.
"But for too many of its employees, Sports Direct is a bad place to work. This is not about exceptional use of zero-hours contracts for short term or seasonal work which some employers and workers may find convenient.
"This is the way Sports Direct employs the vast majority of its workforce. These Victorian practices have no place in the 21st Century."
Ashley has 400 Sports Direct stores across Britain and is estimated to have 17,000 people on zero-hours contracts.
