P&O Ferries conducted a study last year into options to sustain the company which calculated it would cost £309 million to keep the business going while consulting with staff over job losses.
It decided against a full staff consultation over its plans to cut almost 800 jobs, a move which has attracted a huge backlash from unions and politicians.
A company source said the study calculated it would cost £309 million to keep the business going through a consultation period of at least three months, adding there was no guarantee of recovery.
Months of consultations would have undermined the business, caused disruption which would have led to customers leaving to competitors, dealing a “fatal blow” to P&O, the source told the PA news agency.
P&O believes it has safeguarded the long-term future of the company and the livelihoods of 2,200 employees.
A P&O spokesperson said: “Over 90% of seafarers affected are in discussions to progress with the severance offers.
“We are sorry to the people affected and their families for the impact it’s had on them. They’ve lost their jobs and there is anger and shock, which we completely understand.
“We needed fundamental change to make the business viable. This was an incredibly difficult decision that we wrestled with but once we knew it was the only way to save the business, we had to act.
“All other routes led to the loss of 3,000 jobs and the closure of P&O Ferries.
“In making this hard choice we have guaranteed the future viability of P&O Ferries and secured Britain’s trading capacity.
“We are committed to ensuring the continued and ongoing support for all those former and current employees affected.”
The company said the settlement with its workers is believed to be the largest compensation package in the British Marine Sector.
A total of 40 employees are receiving over £100,000 and in some cases are over £170,000, said P&O.
The total value of the financial settlement is over £36 million.
Protests were held in Liverpool, Hull and Dover on Saturday and more are planned in the coming days.
The Rail, Maritime and Transport and Nautilus International unions are urging the company to reverse the sackings and for the Government to take action against P&O.
A ship operated by the ferry firm was detained for being “unfit to sail” on Friday.
The European Causeway vessel was held at the port of Larne in Northern Ireland due to “failures on crew familiarisation, vessel documentation and crew training”, the Maritime and Coastguard Agency (MCA) said.
Prime minister Boris Johnson has joined calls for P&O’s chief executive to resign.
Peter Hebblethwaite admitted to MPs that the firm broke the law by not consulting over the sackings.
Mick Lynch, general secretary of the Rail, Maritime and Transport union, said: “The campaign to get the workers back on the ships, operating these crucial ferry links safely goes on and the company need to face up to the hard facts and take responsibility for their grotesque actions.”