Newcastle United owner Mike Ashley has been branded 'a monster of a man' for the way his Sports Direct company treats staff.
The criticism came in the House of Commons, where the sportswear firm came under fire over claims it pays its workers less than the minimum wage.
Veteran Labour MP Dennis Skinner described Mr Ashley as a "monster of a man" as he addressed the concerns about the Shirebrook warehouse in his constituency.
The Bolsover MP said: "I don't think you should expect any social responsibility from the man that controls Sports Direct in my constituency at the warehouse at Shirebrook on a pit site.
"That man has not made £6 billion because he is a considerate employer.
"He is a monster of a man that doesn't even reply to MPs' letters - I've sent him many.
"He's got £6 billion and is on the Sunday Times Rich List because he's the type of man that will not take any notice of HMRC unless this Government really means business.
"This man Mike Ashley would fit very nicely on millionaire's row along with his pals so this will be a test of the minister's mettle.
"Get stuck in".
Business Minister Nick Boles suggested Sports Direct could face Government action, even though no employees have made individual complaints to HM Revenue and Customs (HMRC).
He said the tax authority can take enforcement action in sectors of concern, adding "they will be listening to this debate".
He was replying to an urgent question from senior Labour MP Chuka Umunna, who described the company as a "bad advert for British business".
Sports Direct faces allegations in The Guardian newspaper that it forces compulsory unpaid searches taking around 15 minutes on staff as they leave, while also docking wages for clocking in just one minute late.
Mr Umunna asked whether such practices were legal under minimum wage law, adding: "We know enough about the practices of Sports Direct plc, which has a branch in my constituency, to conclude that this company is a bad advert for British business and one with a culture of fear in the workplace which we would not wish to see repeated elsewhere.
"As the Institute of Directors said, it is a scar on British business."
He also revealed that employees were too afraid of losing their jobs to complain to HMRC.
Mr Umunna said: "Many of them, all of them, are refusing to come forward in the warehouses concerned for fear of the repercussions that follow.
"Why can HMRC not go ahead and carry out an investigation in this case which surely will render other evidence without workers being required to put their necks on the line?"
He went on: "No doubt the action of the employer concerned in this case will be to say we complied with the law, but surely what they need to understand is actually the British public expect a lot more from them.
"We often don't do things that we're allowed to do by the law because we don't think that is the right way in treating our fellow citizens and surely that should apply to the company in this case."
Replying, Mr Boles said the minimum expected of employers was that they comply with the law but that large companies like Sports Direct should also be "good citizens".
He said: "Obeying the law is the minimum we expect of employers.
"We expect employers to behave responsibly and to be good citizens and we would hope that they would not be satisfied just with obeying the law, that they would want to go a great deal further and I know that employers who are large and profitable in a sense, our expectations of their behaviour is even greater than that of the others."