P&O Ferries has left ferry passengers and workers in limbo after suspending all of its sailings, including those from Cairnryan.

The ferry operator – which runs a service from Scotland to Northern Ireland – said in an internal statement it will make “a major announcement” which will “secure the long-term viability of P&O Ferries”.

UPDATE: P&O makes 800 workers redundant and cancels all sailings

Rail, Maritime and Transport (RMT) union general secretary Mick Lynch said there is “growing speculation that the company are today planning to sack hundreds of UK seafarers and replace them with foreign labour”.

He added: “We have instructed our members to remain on board and are demanding our members across P&O’s UK operations are protected, and that the Secretary of State intervenes to save UK seafarers from the dole queue.”

A crew member, who wished to remain anonymous, told KentOnline: “As of effect from today all our contracts have been terminated and we’ve all been made redundant.”

P&O Ferries said in the statement that “to facilitate this announcement all our vessels have been asked to discharge their passengers and cargo and stand by for further instructions”.

It added: “This means we’re expecting all our ports to experience serious disruption today.”

UK Transport Secretary Grant Shapps told the House of Commons he is “concerned” by the situation.

He said: “I understand they have temporarily paused their operations and that’s causing disruption at the short straits – Calais-Dover – as well as some other ports.

“I’m working with the Kent Resilience Forum and I’ve just instructed them to become intricately involved, and other partners in this, and we’ll be taking steps later today – including ensuring that my officials will be having urgent discussions with P&O about the situation, particularly of concern for their workers.”

Nicola Sturgeon was asked about the situation at First Minister’s Questions.

She told MSPs: “Obviously for Scotland the relevant issue here is the Cairnryan-Larne route, and we’ll pay particular attention to any implications for that. That obviously supports a number of sailings every day.

“This will also be a seriously worrying time for those who work for P&O and I certainly hope that what we are seeing here – I know this has been a difficult time with the pandemic for ferry operators, and I don’t underestimate that – but I hope we are not about to see a mass-scale fire and rehire situation.

“So this will be a worrying time for everybody. And we will engage very closely with all those involved and of course keep Parliament fully updated.”

The National: Scottish First Minister Nicola Sturgeon meets with Ukrainian nationals, staff and volunteers working with the Scottish Refugee Council in Glasgow, as work is underway to prepare for the arrival of people displaced from Ukraine. Picture date: Wednesday

P&O Ferries, which transports passengers and freight, has nearly 4000 employees.

It was bought by Dubai-based logistics giant DP World for £322 million in 2019.

It operates four routes: Cairnryan to Larne; Dover to Calais; Hull to Rotterdam and Liverpool to Dublin.

Sailings between Hull and Zeebrugge, Belgium, were axed in January 2021.

Responding to Thursday's announcement, STUC General Secretary Roz Foyer said: “This is a damning, outrageous move from P&O and we offer our full support to the RMT Union and all their members.

“We cannot – and will not - permit hundreds of workers to be sacked on the spot to be replaced by cheaper labour whilst P&O scramble to remain viable.

“We need to see an urgent statement from both the UK Government and the Scottish Government on how they intend to halt this scandalous misuse of employer power.

Following the coronavirus outbreak, P&O Ferries warned in May 2020 that around 1100 workers could lose their jobs as part of a plan to make the business “viable and sustainable”.

A spokesman for the firm said: “P&O Ferries is not going into liquidation.

“We have asked all ships to come alongside, in preparation for a company announcement.

“Until then, services from P&O will not be running and we are advising travellers of alternative arrangements.”

Stormont Assembly members whose constituency incorporates the port of Larne expressed concern about the potential implications for the route to Cairnryan.

East Antrim MLA John Stewart, who has relatives who work at the port, said staff were uncertain about what would be announced.

“The information is being nothing more than drip-fed to them,” the Ulster Unionist MLA told BBC Radio Ulster.

He said it is a “worrying” development.

“For the staff, for Larne port itself, particularly for the local effect here, and also for businesses and passengers that regularly use that service, it’s an invaluable local service over to Cairnryan and I think this news will be deeply worrying for all of them, especially in the absence of any concrete information as to what the long-term strategy is going to be.”

The company that would become P&O Ferries was founded in 1837 after signing a government contract to transport post by boat between London and the Iberian Peninsula.