P&O Ferries’ hopes of resuming cross-Channel services between Dover and Calais later this week appear to have suffered a big blow after the Spirit of Britain was further detained, according to the French authorities.

The company, universally condemned for its treatment of almost 800 seafarers who were sacked without notice last month, had planned for the vessel’s new crew to begin crossings from Good Friday.

Such a move would have, potentially, enabled the company to support the effort to clear backlogs of freight traffic, mostly caused by the absence of its three Dover-based ships, and ferry Easter holidaymakers to France.

But the French government agency responsible for maritime safety declared that the Spirit of Britain had been detained on Tuesday.

It followed a two-day reinspection of the vessel by the Maritime & Coastguard Agency, which was expected to release a statement later on Tuesday evening to explain why she was, apparently, still not fit to be cleared for sea.