The UK has detained five of six Global Cruise Lines ships inspected after crew raised welfare concerns.
The Maritime and Coastguard Agency (MCA) said the 16,144-gt Astoria (built 1948), 20,704-gt Astor (built 1987), 63,786-gt Columbus (built 1989) and 56,000-gt Vasco da Gama (built 1993) were all held at Tilbury after checks on Friday.
The 22,080-GT Marco Polo (built 1965) at Bristol has also been detained.
