Shadow chancellor John McDonnell has joined calls for Sir Philip Green to be stripped of his knighthood if he boycotts a grilling by MPs over the collapse of BHS.
The former owner of BHS is refusing to give evidence to a parliamentary inquiry unless Labour's Frank Field, who he accuses of bias, steps aside as chair of the work and pensions select committee.
Writing in The Observer, Mr McDonnell said the threatened no-show was an "insult to the British public" and the demise of the retailer "makes a mockery of those in business who are doing the right thing".
He said recent scandals had exposed "a growing elite who think they are above the law and above British decency" and vowed to implement "anti-freeloader" measures if Labour returned to power.
In a direct attack on Sir Philip, he wrote: "This week, we may witness Philip Green (I refuse to use his title) justify his actions at BHS. The fact he feels he can threaten to subvert parliament is an insult to the British public.
"If he refuses to come before parliament, Green should be stripped of his knighthood. Parliament should have the right to strip honours from individuals, in my view.
"This would remove the secret committee network and help restore public faith in the honours system."
The work and pensions select committee - along with the business select committee - are investigating the £1 sale of the retailer to ex-bankrupt Dominic Chappell and the subsequent collapse that left a £571m black hole in its pension fund.
A group of Tory MPs have already announced their intentions to write to the honours committee calling on it to strip Sir Philip of his knighthood, unless he promises to cover the BHS pension fund black hole.
Sir Philip threatened the no-show after Mr Field said the panel would "laugh" if the wealthy businessman offered less than £600m to save the pensions of the workforce.
"I am not prepared to participate in a process which has not even the pretence of fairness and objectivity and which has as its primary objective the destruction of my reputation," he told him in a letter.
Mr Field dismissed the complaint and business committee chair Iain Wright said Sir Philip risked appearing to be "running scared" and having "something to hide" if he stayed away.