First Minister Nicola Sturgeon has spoken directly to the boss of P&O Ferries to express her “utter disgust” at its treatment of employees.

In a shock announcement today, the firm revealed it would be sacking 800 workers and has cancelled all of its sailings in the coming days, including the service between Cairnryan and Larne in Northern Ireland.

Workers currently onboard ships were instructed by unions not to leave. Coaches carrying agency workers hired to replace the P&O staff are parked near ships at ports.

There were reports that balaclava-clad security teams were sent on to ferries to remove the sacked staff.

Sturgeon has now held a one-on-one chat with P&O CEO Janette Bell where she said she slammed the company for its “appalling” treatment of its staff.

On social media, she hit out at the practice of fire and rehire which she claimed “offends the basic principles of fair work”.

Rustom Tata, chairman of law firm DMH Standard, added: “Some of the headlines have been about the practice of ‘fire and rehire’ and the need for it to be outlawed.

"That is probably slightly missing the mark.

"While the current law does allow ‘fire and rehire’, that is usually in relation to the same employees. The employer says that it cannot afford the current levels of pay etc, seeks to renegotiate, and in the absence of agreement serves notice to terminate employment while saying that it remains prepared to employ the individual on new terms.

"The issue here is that current staff, from a heavily unionised workforce, seem to be set to be replaced with a number of agency staff. That is effectively seeking to avoid having to renegotiate terms with staff and their representatives. Redundancy notices are being issued, with the P&O apparently having recognised the unlawfulness of its actions with comments that enhanced compensation will be paid.

"For those staff who have been, or are about to be dismissed, they will certainly have claims for unfair dismissal.

"There is a further potential twist for those staff who are refusing to leave their vessels.”

The company, bought by Dubai-based logistics giant DP World in 2019, announced it has fired seafarers as it is “not a viable business”.

Green MSP Ross Greer said he supported workers remaining on ships. He added: “P&O should be universally condemned for this attempt to sack their entire UK workforce and replace them with agency staff on worse pay and conditions.

“The RMT union has rightly opposed this action in the strongest possible terms and the Scottish Greens support their efforts to save their members' jobs, including by remaining on their vessels until this is resolved.”

P&O Ferries said in a statement: “We have made a £100 million loss year on year, which has been covered by our parent DP World. This is not sustainable.

“Our survival is dependent on making swift and significant changes now. Without these changes there is no future for P&O Ferries.”