The boss of P&O Ferries has refused to reinstate nearly 800 sacked staff as he claimed the move would "cause the company's collapse".
Chief executive Peter Hebblethwaite told the Government that the firm would not U-turn on the decision to fire hundreds of seafarers to replace them with cheaper agency staff.
Transport Secretary Grant Shapps gave the firm an ultimatum to rehire staff on their previous wages or face consequences.
But the P&O boss wrote to Mr Shapps claiming his request "ignores the situation's fundamental and factual realities".
Re-employing the sacked workers on their previous wages would "deliberately cause the company's collapse, resulting in the irretrievable loss of an additional 2,200 jobs", the letter said.
"I cannot imagine that you would wish to compel an employer to bring about its own downfall, affecting not hundreds but thousands of families."
When P&O Ferries announced its decision to replace its crews with cheaper agency workers, it stated that the business needed to cut costs to survive as it was losing £100 million a year.
Mr Hebblethwaite also rejected Mr Shapps' request that Thursday's deadline for sacked workers to accept redundancy offers is delayed, as more than 765 of the 786 affected people have "taken steps to accept the settlement offer".
He wrote: "These are legally binding agreements, and crew members who have entered them will rightly expect us to comply with their terms."
He also resisted calls for him to quit - despite Mr Shapps describing his position as "untenable".
Mr Hebblethwaite wrote: "I am fully cognisant of the reputational cost to the P&O Ferries brand and me personally.
"That notwithstanding, I am compelled to discharge my duties for this historical company, saving the jobs of the 2,200 dedicated employees who continue working for P&O Ferries and providing for the effective operation of the trade routes upon which this country depends."
It comes after he admitted to MPs last week that the firm "chose" to break the law by failing to consult staff and unions before sacking staff by Zoom call.
The ferry boss also confirmed the average wage among 'replacement' employees on P&O vessels will be £5.50 an hour - well below the minimum wage.
The chairmen of the Commons’ transport and business select committees urged the Government to strip P&O Ferries of its licence on Monday.
Tory MP Huw Merriman and Labour MP Darren Jones wrote: “Our immediate concern is the welfare and employment rights of the 800 seafarers made redundant by P&O Ferries.
“Government has not moved sufficiently quickly to support them. Going forward, ministers must prioritise the wellbeing of those 800 seafarers.”
They added: “The Government should prosecute P&O Ferries and remove its licence to operate in the UK.”
