Cruise & Maritime Voyages’ ship the Astoria has been detained at Tilbury on the orders of the UK’s Maritime and Coastguard Agency (MCA).

Port authorities boarded five Cruise & Maritime Voyages (CMV) ships in Tilbury, near London, and a sixth at Bristol Avonmouth amid “serious concerns” about the welfare of almost 1,500 crew members.

Many of the crew have been stranded since cruises were cancelled in March.

Katy Ware, MCA director of maritime safety and standards, confirmed: “We have used our powers as the port state control authority to carry out this detention so that we can investigate more fully.”

The MCA detained the Astoria on Thursday and is inspecting five other ships owned by CMV and managed by shipping services company Global Cruise Lines.

It said: “The detention is a preventative measure in line with UK regulations in order that a full inspection of the ship related to the maritime labour convention can be carried out before its intended departure. It cannot leave the port until the inspection is completed.

“Five other ships in the same company – Global Cruise Lines Ltd – four others based at Tilbury and one at Bristol, are also being inspected.

“The MCA has taken this action following a number of serious concerns raised about the welfare of the crew.”

The All India Seafarer and General Workers Union wrote to India’s foreign office this week requesting the urgent repatriation of Astoria crew members, saying some of the crew had begun a hunger strike.

CMV said 1,449 crew were on board the six ships and confirmed 50 crew members on the Astoria had “commenced a strike, including no longer performing routine maintenance work”.

The company also confirmed a crew member on another ship at Tilbury, the Vasco da Gama, had died “following a heart attack”.

CMV has been in urgent talks to raise funds after failing to secure a £25 million loan under the UK government’s Coronavirus Large Business Interruption Loan Scheme (CIBILS).

The failure led to the abandonment of a refinancing deal with private equity firm Novalpina Capital and CMV’s creditors.

Christian Verhounig, chief executive, said: “Our crew have endured a prolonged period quarantined on board our ships during lockdown and are understandably anxious and distressed.”

He said the “vast majority of European crew had been repatriated” and the group was in “high level talks with Indian and other international governments” on repatriation.

The Astoria has been docked in Tilbury since mid-March after leaving Mexico in mid-February.

The Vasco da Gama arrived in Tilbury on May 1, having sailed from Australia.

Of the other CMV ships at Tilbury, the Astor arrived on May 27 after leaving Réunion in the Indian Ocean on March 14, the Columbus has been in Tilbury since April after sailing from Sri Lanka, and the Magellan arrived on April 8 from Iceland.

The sixth ship has been in Avonmouth since March 22 after sailing from Jordan.