But unions have reported that agency staff are walking off the job after discovering how P&O treated its crew.

Experts say that recruiting an entirely new crew that can operate a ship safely is almost impossible in the timescales proposed by P&O. Replacing an entire crew normally involves a handover of four to six weeks, but P&O is aiming to get ships sailing again within a week.

P&O says customers should expect “significant disruption” to P&O Ferries services over the next few days. Its website directs passengers with bookings to its Twitter feed @POferriesupdate.

The Twitter feed reveals the chaos caused by the job losses. P&O sailings between Dover and Calais are cancelled but P&O says passengers should arrive at the port as normal and it will book them on an alternative carrier “as soon as possible”.

P&O services between Larne and Cairnryan remain suspended. P&O says it can’t arrange alternative bookings for customers booked on this route and is telling customers to “seek alternatives themselves”.

Another Tweet this morning explained the situation regarding the Hull to Rotterdam route. It said: “#POHull #PORotterdam services tonight are cancelled. If your journey is not essential, please do not travel today. We apologise for the inconvenience and for the late notice. Those with essential travel needs will be guided by our port teams.”

Adam French, Which? consumer rights expert, said: “If your ferry service is cancelled or departure is delayed for more than 90 minutes, you should be offered the choice between an alternative sailing at the earliest opportunity at no additional cost and reimbursement of the ticket price within seven days.

“If you opt for an alternative crossing, you may still be entitled to claim compensation for the delay to your original journey, and the company should provide you with snacks, meals and refreshments, provided they are available or can reasonably be supplied. If your journey is delayed or cancelled and an overnight stay becomes necessary, the ferry or cruise operator must offer you accommodation free of charge, if possible.”

Staff replaced with cheaper foreign labour

P&O suspended all services last Thursday then announced it was making 800 staff redundant in a pre-recorded Zoom call in a move that outraged unions.

Crew were given five minutes to get their stuff and get off their ships – with security personnel hired to remove any workers who refused to leave.

P&O said its ships would subsequently be staffed with “agency workers” to the outrage of unions.

RMT union says P&O ferry crews at Dover have been replaced by Indian seafarers being paid 2.38 dollars (£1.80) an hour.

Mick Lynch, RMT general secretary, said: “The news that the seafarers now on ships in British ports are to be paid 2.38 dollars an hour is a shocking exploitation of those Seafarers and another gut-wrenching betrayal of those who have been sacked.

“The rule of law and acceptable norms of decent employment and behaviour have completely broken down beneath the white cliffs of Dover and in other ports yet five days into this national crisis the government has done nothing to stop it.”

“These ships of shame must not be allowed to sail. The government has to step in now and take control before it’s too late.”

RMT also reported that P&O owners DP World refuse to meet union leaders over the jobs carve-up.

Another union, Nautilus International, says it has been informed that large numbers of agency crew have already walked off the job.

Nautilus International said that on one vessel there is now only a single replacement engineer remaining. The other five all left the ship after discovering that they had been hired to take the jobs of P&O crew who were thrown off the vessel last week.

Nautilus believes that this vessel is now breaching regulations by burning heavy fuel oil in port, as the crew are unfamiliar with the vessel’s operation.

Deck officers are also leaving and the company is being forced to try recruiting from further afield to fill the gaps.

Martyn Gray, Nautilus executive officer, said: “The company has been producing crew lists and having to revise them immediately to strike off workers who have left the job,’

“The company are saying it will restart sailings from Dover on Thursday but we are sceptical that it will be able to do so. These actions by agency crew, acting in solidarity with the fired workers, are hindering the company. P&O must find a completely new crew for each vessel, and the people they do manage to recruit are leaving straightaway.”