A “package of measures” will “block” P&O Ferries’ plan to replace 800 seafarers with agency workers paid below the UK’s minimum wage, according to Transport Secretary, Grant Shapps.

The company caused outrage after sacking its crews with no notice on March 17.

In a letter to P&O chief executive, Peter Hebblethwaite, Mr Shapps wrote: “I will be bringing a comprehensive package of measures to Parliament to ensure that seafarers are protected against these types of actions in the way that Parliament and this Government already intended.

“Through that package, I intend to block the outcome that P&O Ferries has pursued, including paying workers less than the minimum wage.”

The measures could be unveiled on Wednesday.

Meanwhile, the Maritime and Coastguard Agency (MCA) said it is inspecting P&O Ferries’ ship Pride of Kent at the Port of Dover to ensure it is safe to go to sea with its new crew, even without passengers or cargo.

A full inspection would be required at a later date before it could resume commercial operations.

The MCA said another of the firm’s vessels, European Causeway, remains under detention in Larne, Northern Ireland after “failures on crew familiarisation, vessel documentation and crew training” were discovered.

The minimum wage in the UK for people aged 23 and above is £8.91 per hour.

Mr Hebblethwaite, whose basic annual salary is £325,000, told MPs on March 24 the average pay of the agency crew is £5.50 per hour.

He said this is “an international seafaring model that is consistent with models throughout the globe and our competitors”.

Irish Ferries began operating on the Dover to Calais route in June 2021 in competition with P&O Ferries.

On March 23, Prime Minister Boris Johnson told Parliament: “We’re going to make sure that everybody working in the UK exclusive economic zone gets paid the living wage and we’ll do it as fast as we possibly can.”

Mr Shapps told Mr Hebblethwaite he has “one further opportunity” to reinstate the sacked workers on their previous wages.

He went on: “Our package of measures will prevent the law being broken, even when knowingly attempted.

“With this point in mind, I would also suggest that the deadline imposed on seafarers to respond to your redundancy offer by March 31 is dropped.

“Given that we intend to ensure such outcomes are prevented by laws, which we will ensure that you cannot simply choose to ignore, I believe you will be left with little choice but to reverse your decision in any case.”

Mr Shapps reiterated his call for him to resign, accusing him of “contempt for workers” and describing his position as “untenable”.

In his evidence to a joint session of the Commons’ transport and business select committees, Mr Hebblethwaite admitted the company broke the law by not consulting with trade unions before sacking workers.

The chairs of the committees, Tory MP Huw Merriman and Labour MP Darren Jones, wrote to Mr Shapps and Business Secretary, Kwasi Kwarteng, on Monday urging them to address the “appalling” evidence given by the chief executive.

Among a series of points raised, the letter stated that the Government “has not moved sufficiently quickly” to support the sacked workers, and “must prioritise” their wellbeing.

It also called on the Government to “prosecute P&O Ferries and remove its licence to operate in the UK”.

Bosses from ferry firms DFDS and Stena Lines were due to hold talks with Department for Transport officials on Monday amid concerns over chaos at ports during the Easter holidays because P&O’s services are disrupted.

The department confirmed the meeting was taking place, but declined to comment on the topics for discussion.

In October, Mick Lynch, general secretary of the Rail, Maritime and Transport (RMT) union, issued a statement warning about Irish Ferries’ low-cost labour model.

He claimed the company uses workers from Poland and other European countries paid “well below the national minimum wage”.

The Government “refused to make any changes that would require Irish Ferries to employ and train local seafarers,” he added.

Irish Ferries did not immediately respond to a request for a comment on Monday.

A P&O Ferries spokesman said: “We fully welcome the Government’s commitment to increasing the minimum wage for all seafarers working in British waters.

“From the outset, we have called for a level playing field when it comes to pay and conditions on British ferry routes.

“Our announcement is not about reducing seafarer’s wages, it is to enable us to have a fully flexible crewing model that allows us to meet the demands of our customers.

“The predicted savings we announced are not solely coming from the reduction in wages, but from removing job duplication and the benefits we will see from increased flexibility.”

TUC general secretary Frances O’Grady said: “Closing the loophole that lets rogue employers pay less than minimum wage at sea is long overdue but it is just half a step forward.

“Ministers must make sure that P&O staff are reinstated on their previous pay – a union-negotiated rate that is significantly higher than the national minimum wage.

“And if ministers are opening up the possibility of legislative change, then they should bring forward their long-promised employment bill, to outlaw fire and rehire and root out bad employers across the economy.”

A second P&O ferry, the Pride of Kent, has been detained after being boarded by Maritime and Coastguard Agency (MCA) officials in Dover on Monday.

It follows the detention of a P&O vessel which was held in the Northern Ireland port of Larne on Friday due to “failures on crew familiarisation, vessel documentation and crew training”.

A spokesperson for the MCA said: “Our surveyors are in the process of detaining the Pride of Kent. We are awaiting confirmation of all the detainable items.”

The Rail, Maritime and Transport union said it believed the MCA acted because of “ multiple safety and operational breaches”, including the wearing of breathing apparatus.

The union repeated its demand that the Government seize P&O’s entire fleet and take action to get them back in service with the sacked crew reinstated.

General secretary Mick Lynch said: “The seizing of the Pride of Kent by the MCA this evening should be adequate evidence for the Government that the gangster capitalist outfit P&O are not fit and proper to run a safe service after the jobs massacre.

“It’s rare enough for the MCA to impound a ferry but P&O have now had two in a week after the jobs carve up which speaks volumes about the dire state of their operation.

“It’s now high time for these important vessels to be taken over under public control with the sacked crews reinstated as the only way to get these crucial ferry routes back running safely.”