Ironically, the crew of the Type 45 frigate have been previously deployed in the Caribbean to combat drug smuggling.

"The Royal Navy does not tolerate misuse of drugs by its personnel and internal action is underway against all 18 individuals," said a spokesperson for the Ministry of Defence (MoD).

"Notwithstanding the numbers involved in this single unprecedented incident which is being treated very seriously, it has not affected the ship's ability to do its job."

The MoD were keen to downplay the significance of the bust, claiming that drug use in the Navy was a fraction of that in the civilian world.

"These results must be understood in context," the MoD spokesperson said.

"Tests show that drug misuse is almost 20 times more common in civilian work places than it is in the Navy."

"Positive test rates in the Navy last year averaged less than 0.4%, compared with over 7% in civilian workplaces."

"The UK Ministry of Defence conducts Europe's largest compulsory drug testing programme and this has significantly reduced drug misuse among service personnel."

"We are not complacent though and our compulsory drug tests will continue to expose those few that let the rest down."

HMS Liverpool was recently charged with defending the Falkland Islands, and some say that the bust has compromised the reputation of the Royal Navy.

"The worst aspect of this scandal is that HMS Liverpool is supposed to be guarding the Falkland Islands and such a large drugs bust hardly does wonders for confidence," said a senior Naval source to The Sun newspaper.

The eighteen are now subject to disciplinary action -- but it is almost certain that they will all be dismissed from the Navy.

Five soldiers from the King's Troop Royal Horse Artillery were recently dismissed for cocaine use, in line with the zero tolerance policy found in the armed forces.