The Dubai-based owner of P&O Ferries has reported record-breaking profits just months after sacking 800 of its UK-based workers without notice.

DP World, which is ultimately owned by the Dubai royal family, said in March that firing 786 P&O seafarers and replacing them with much cheaper agency workers was the only way to ensure the “future viability” of the historic ferry business.

However, on Thursday Sultan Ahmed bin Sulayem, DP World’s chair and chief executive, announced the company had increased its first-half revenues by 60 per cent to $7.9 billion (€7.8bn) and profits had risen by more than 50 per cent to a record $721 million.

“We are delighted to report a record set of first-half results with … attributable earnings [profits] rising 51.8 per cent,” he said in the company’s earning’s statement on Thursday. “Overall the strong first-half performance leaves us well placed to deliver improved full-year results.”

DP World did not give separate details on the performance of its ferries business in its results, but the bulk of revenues and profits come from other divisions. It operates ports in 78 countries on six continents including London Gateway and Southampton, and bought P&O in 2006 for £3.3 billion.

DP World had told a UK parliamentary inquiry that P&O “had no future” unless it sacked the workers. At a Commons hearing in March, Peter Hebblethwaite, the boss of P&O, said the company had chosen to break the law and sack the 800 workers without notice or consultation because “no union could accept our proposals”.

The staff were told in video calls on the ships that it was their “final day of employment” and ordered off the ferries. – Guardian service