P&O Ferries has resumed cross-Channel sailings for the first time since it sacked nearly 800 seafarers.
The vessel Spirit of Britain departed Dover for Calais shortly after 11pm on Tuesday carrying freight customers.
Passenger services are expected to resume early next week.
The company was widely condemned after replacing 786 crew members with cheaper agency staff on March 17.
Chief executive Peter Hebblethwaite told a joint hearing of the Commons’ business and transport committees later that month that P&O Ferries broke the law by not consulting with trade unions before implementing the decision.
Transport Secretary Grant Shapps told MPs on Wednesday that Mr Hebblethwaite’s refusal to resign is “completely unsustainable”.
The Cabinet minister urged P&O Ferries to repay £11 million of furlough money claimed from the Government during the coronavirus pandemic.
He added that the company “will have to pay the minimum wage” when new legislation is introduced.
Rail, Maritime and Transport (RMT) union general secretary Mick Lynch said: “After yesterday’s vessel ran adrift off the coast of Larne, no P&O ferry should set sail on safety grounds.
“Staffing ferries with undertrained, ill-equipped, over-worked and grossly underpaid seafarers blatantly undermines maritime safety.
“Instead of taking that gamble with worker and passenger safety, the Government must step in now and take over the running of all P&O vessels.”
On Tuesday, the Trade Unions Congress called for a public and commercial boycott of the firm, claiming it deserves “pariah status” for the way it treated its employees.
Spirit Of Britain was detained by the Maritime and Coastguard Agency (MCA) on April 12 after safety issues were found, but was cleared to sail on Friday.
European Causeway, which can carry up to 410 passengers, got into difficulty on Tuesday after losing power while sailing between Cairnryan, Scotland and Larne, Northern Ireland.
The Marine Traffic website stated the ferry’s automatic identification system status had been set to “not under command”, which is reserved for use when a vessel is “unable to manoeuvre as required by these rules and is therefore unable to keep out of the way of another vessel”.
A spokesman for P&O Ferries said it had been a temporary issue and the European Causeway had travelled to Larne “under its own propulsion”.
On Wednesday, the MCA said: “Our surveyors are carrying out a full inspection of P&O Ferries vessel European Causeway. This follows the mechanical failure while it was at sea yesterday.
“It is important to note that this does not mean the ferry is under detention but will be inspected before it returns to full service.
“There are no further inspections of P&O Ferries at the moment but we will reinspect when requested by P&O Ferries.”
