“The drugs were hidden in false bottoms in the suitcases and were distributed evenly among the four cases in the cabin.

“There were nine kilos in total.

“The couple appeared in court on December 5. The woman is currently being held at a prison in Tires near Lisbon and the man at prison in Lisbon.

“We believe the couple were given the drugs in a Caribbean island but are still looking into which island at this stage.

“We do not know for sure at the moment where the cocaine was going to be brought ashore. Again that is something that is being probed.

“These are the only arrests so far.”

He added: “The couple were not at all showy and blended in well because most of the other passengers on the cruise liner were elderly.

“They were travelling alone. They didn’t try to protest their innocence after their arrests. They haven’t said anything to police as to how the drugs got in their cases.”

A well-placed source said the cocaine could have been fetched nearly £2 million on the streets of the UK.

A spokesman for Cruise & Maritime Voyages said: “Portuguese police officials attended the Marco Polo in Lisbon last Tuesday (4 December 2018) and detained two passengers who were travelling on board the Cruise & Maritime Voyages’ vessel.