Around a tonne of cocaine worth up to £100 million has been seized at Dover concealed within a shipment of fruit.
The drugs were found in the early hours of Tuesday hidden in pallets that had arrived at the Kent port on a vessel from South America.
Searches have been carried out in Glasgow and Essex as the investigation continues, the National Crime Agency (NCA) said.
Two men have been arrested on suspicion of importing class A drugs: a 40-year-old in Brentwood, Essex, and a 64-year-old in central Glasgow.
Both were questioned before being released under investigation.
The investigation is linked to Operation Venetic, which has so far seen hundreds of arrests across the UK following the infiltration of an encrypted communications platform.
NCA director of investigations Nikki Holland said: “This is a huge seizure of class A drugs, made as a result of some excellent joint working between the NCA and Police Scotland under the Organised Crime Partnership (Scotland), and our Border Force colleagues.
“This operation has prevented a large amount of cocaine from making it on to our streets, we estimate that once adulterated and sold it could have had a street value of up to £100 million.
“So in making this seizure we have taken away a valuable commodity that would have been sold to fund further serious and organised criminality.
“Our investigation into this attempted importation is continuing.”
Angela McLaren, assistant chief constable organised crime, counter terrorism and intelligence, said: “This seizure is undoubtedly a massive setback for serious and organised criminals.
“This operation and our other recent successes underline our unwavering commitment to working with partners, including the NCA, Border Force and SOC Taskforce, to disrupt this sort of criminality.
“Working together we will relentlessly pursue those who seek to bring misery to our communities whether they are in Scotland or elsewhere in the world.”
The Organised Crime Partnership (Scotland) is a covert investigation team comprising of officers and staff from Police Scotland and the NCA.