Sports Direct boss Mike Ashley has pulled out of a meeting with MPs about working conditions at the company because his lawyer cannot make it.
In a fresh twist set to intensify his row with the Business, Innovations and Skills Committee (BIS), Mr Ashley said his legal representative was "unavailable" so he could not attend the session on June 7.
The retail tycoon and Newcastle United boss had been hit with a summons from the committee in March after refusing previous invitations on the grounds that he would not ''stand idle'' while Sports Direct was ''subjected to public vilification''.
The committee has been seeking to question Mr Ashley over working practices at his Shirebrook warehouse, including reports of poor working conditions and the use of controversial zero-hours contracts.
Iain Wright, BIS committee chair, said he was disappointed by the "eleventh-hour notification" after giving Mr Ashley "a notice period of three months to make the necessary arrangements".
He said: "Business leaders regularly come before the committee and answer our questions. Sir Philip Green, for example, has agreed to attend as part of our joint inquiry into BHS.
"Does Mr Ashley, owning and operating a business in a parliamentary democracy, see himself as being beyond such public scrutiny? What has he got to be frightened of?"
The committee has a range options to put pressure on Mr Ashley if he fails to attend a meeting.
These include going to the floor of the House with a special report on Mr Ashley, which would be debated before issuing him with another summons, but with the weight of the entire parliament behind it.
It could also ask Parliament to debate a motion on whether Mr Ashley is a fit and proper person to be in charge of a business, or they could find him in contempt of Parliament for failing to attend a meeting.
Mr Wright said: "As democratically elected MPs, we are responding to serious allegations of exploitative employment-practices and mistreatment of workers at Sports Direct.
"Mr Ashley announced in December he would personally oversee a review of working practices at the Shirebrook warehouse.
"It is entirely reasonable for the Select Committee to ask Mr Ashley to respond to those allegations and comment on how his review - announced over six months ago - is progressing."
The committee said it would decide its next steps when it meets for the session on Tuesday.