P&O has admitted plans to sack almost 800 UK crew came "without warning or prior consultation" as Labour branded the ferry giant a "rogue employer".
In a letter to Tory ministers on Tuesday night, P&O chief executive Peter Hebblethwaite failed to offer any apology after shock mass redundancies last week were revealed to staff in a pre-recorded video.
The company also underlined that all 786 workers were employed with three P&O subsidiaries, based offshore in Jersey rather than the UK, and claimed it did not therefore break UK employment law.
Unions have said P&O is still in breach of British trade union laws, however, and that the company has failed in its duty to consult on mass redundancies before the announcement.
The letter from Mr Hebblethwaite to Business Secretary Kwasi Kwarteng reads: "We know that for our people this redundancy came without warning or prior consultation, and we are painfully aware that this has caused distress for them and their families.
"Restructuring our workforce in this way was not a course of action that we ever wanted to take as an organisation - we did this as a last resort and only after full consideration of all other options."
TUC General Secretary Frances O’Grady has urged Chancellor Rishi Sunak to "come down on P&O like a ton of bricks" in his Spring Statement on Wednesday by ripping up freeport contracts with the firm.
She said: “If P&O is allowed to get away with a slap on the wrist, it will be a green light for employers up and down the land to treat staff like disposable labour.
“The government needs to hit the firm where it really hurts.
“That means suspending all of P&O’s licenses immediately and cancelling its lucrative freeport contracts until all workers have been reinstated.
“The Chancellor must use his statement tomorrow to show that he is willing to stand up to bad bosses. Not a single penny of taxpayers’ money should be given to companies that trample over workers’ rights.”
Mr Hebblethwaite also contested allegations that security staff hired to remove sacked workers were wearing balaclavas or prepared to use force.
He acknowledged the "difficult circumstances of this restructure" but insisted "the teams accompanying the seafarers on our vessels were totally professional in handling this difficult task", adding: "Contrary to rumours, none of our people wore balaclavas nor were they directed to use handcuffs nor force."
UK ministers are weighing up how to respond.
Shadow Transport Secretary Louise Haigh said: “P&O Ferries have not shown a shred of regret for the livelihoods they have destroyed.
“Ministers urgently need to explain what steps they will take to hold this rogue employer to account.
“Ministers must ensure they cannot get away with trampling over the rights of British workers, and ensure this can never happen again."
The news came as P&O said it is offering more than £36 million in compensation to sacked staff, with 40 employees in line for payments of more than £100,000.
The company said payouts would be linked to the period of service, and in some cases exceed £170,000.
The total value of the settlement is £36,541,648, with no worker set to receive less than £15,000, the company said.
Employees are also being given support to find a new job at sea or onshore.
The ferry giant said that 575 of the 786 seafarers affected are in discussions to progress with the severance offers.
A spokesman for P&O Ferries said: “This has been an incredibly tough decision for the business: to make this choice or face taking the company into administration.
“This would have meant the loss of 3,000 jobs and the end of P&O Ferries.
“In making this hard choice, we have guaranteed the future viability of P&O Ferries, avoided large-scale and lengthy disruption, and secured Britain’s trading capacity.”
But Mick Lynch, general secretary of the Rail, Maritime and Transport union (RMT), said that “the pay in lieu of notice is not compensation”.
“It is just a payment staff are contractually entitled to as there was no notice given,” he said.
“The way that the package has been structured is pure blackmail and threats – that if staff do not sign up and give away their jobs and their legal right to take the company to an employment tribunal, they will receive a fraction of the amount put to them.
“The actions of P&O demonstrate the weakness of employment law and protections in the UK. P&O have flagrantly breached the law and abandoned any standards of workplace decency.
“They have ripped away the jobs, careers and pensions of our members and thrown them on the dole with the threat that if they do not sign up and give away their rights they will lose many thousands of pounds in payments."
