P&O Ferries has replaced the UK crews it sacked without warning last week with Indian seafarers paid just 2.38 US dollars (£1.81) an hour, a union has said.
The replacements are being paid well below the minimum wage in the UK, The Rail, Maritime and Transport union (RMT) said.
General secretary Mick Lynch said: "The news that the seafarers now on ships in British ports are to be paid 2.38 dollars an hour is a shocking exploitation of those seafarers and another gut-wrenching betrayal of those who have been sacked.