Chancellor Rishi Sunak told the BBC at the weekend the firm’s move was "awful" and wrong" and said the government was exploring the legality of P&O’s actions.

Business secretary Kwasi Kwarteng wrote to P&O chief executive Peter Hebblethwaite on Friday (18 March), describing the company’s actions as "appalling".

Labour, meanwhile, is expected to force an emergency vote in parliament early this week demanding the government take action on so-called "fire and rehire" moves.

A leaked memo, details of which were published by the Sunday Times at the weekend, suggested that Whitehall officials may have been aware of the firm’s plans but didn’t intervene.

"We understand P&O Ferries have an intention to try and re-employ many staff on new terms and conditions or use agency staff to restart routes; they estimate disruption to services lasting 10 days," read part of the memo reported by the paper.

A Department for Transport spokesperson told the BBC the memo was sent before ministers were advised of the full details. Transport secretary Grant Shapps has called on P&O to meet with workers and reconsider.

The RMT union, the union representing P&O Ferries seafarers, has warned it believes employment standards at P&O would fall if action to support workers rights wasn’t forthcoming from government.

A parliamentary debate is fixed for Monday (21 March). P&O Ferries has said it took the decision as a "last resort", claiming the firm – owned by Dubai’s DP World – would otherwise have collapsed.

P&O ordered its ferries to return to port on Thursday morning (17 March). Staff were told that morning their roles were to be terminated with immediate effect on grounds of redundancy.