The Brit couple face a lengthy stint behind bars if they are found guilty of smuggling.
Cops in Portugal arrested the OAPs after conducting a search of their cabin and finding a “large amount of cocaine” inside their bags on December 4 last year.
The duo, aged 70 and 72, were snared after the ship they were travelling on from the Bahamas docked at Lisbon Port’s Cruise Terminal.
Now Roger and Sue Clarke have been charged with smuggling and will not leave Portuguese prison before trial.
“Despite all inquiries carried out to identify the people believed to have recruited them, it has not been possible to discover these individuals”
Prosecutors admitted they have been unable to identify the drug lords who “recruited” the two pensioners.
Portuguese cops acted on a tip-off from Brit officials and boarded the MC Marco Polo boat during the penultimate stop of the 33-day £3,000-per-head cruise.
Drug enforcement agents conducting the raid found nearly 20lbs of the potent Class-A drug were found hidden inside four suitcases in their cabin.
Roger, of St Mary’s Cray near Bromley, Kent, had allegedly bragged on board of buying it for a bargain on the Caribbean island of St Lucia.
An indictment made public yesterday reveals Portuguese prosecutors have shelved their probe into the Brit pair’s alleged paymasters.
Prosecutors said: “Despite all inquiries carried out to identify the people believed to have recruited them, it has not been possible to discover these individuals’ full identities.
“The suspects acted together with the purpose of receiving and carrying the cocaine and the objective of handing it over to a third party for money.”
Prosecutors also denied the Clarkes’ of being released on bail before their trial by describing the evidence against them as “extremely strong”.
State prosecutors have not said if the couple had co-operated with authorities.
Under Portuguese law the crime they have been charged with carries a prison sentence of up to 12 years.