UK authorities seized almost 1.3 tons of heroin with a street value of £120 million ($148 million) from a container ship, in the nation's largest ever bust involving the drug.
Officers from the National Crime Agency (NCA) and the Border Force found the heroin hidden in a cargo of towels and bathrobes when the container ship MV Gibraltar docked at Felixstowe on August 30, according to an NCA statement.
The 1,297 kilogram haul would sell for £27 million at wholesale prices, but its value would rocket to £120 million at street level, the NCA said.
The haul follows a 398 kilogram seizure at the port of Felixstowe in August.
"This is a record heroin seizure in the UK and one of the largest ever in Europe," said Matt Horne, NCA deputy director of investigations.
"It will have denied organised crime tens of millions of pounds in profits."
NCA intelligence indicated that the ship would be carrying heroin to the Belgian port of Antwerp, via Felixstowe.
Officers removed the drugs in an operation that lasted almost six hours, and replaced the container before it continued its voyage to Antwerp.
Upon arrival in Belgium on September 1, the container was unloaded and driven to Rotterdam, in the Netherlands.
Dutch and Belgian law enforcement officers tracked its progress and later arrested four people who were unloading in Rotterdam.
"This is a huge seizure -- there is no other word for it given the quantities involved -- which has kept dangerous drugs off the streets of the UK and mainland Europe," said Jenny Sharp, Border Force Assistant Director at Felixstowe.
On August 2, officers made another seizure of 398 kilograms of heroin from a container at Felixstowe, also hidden among towels and bathrobes.
That load, worth £40 million ($48 million) at street level, was removed and law enforcement tracked the container to Rotterdam via Antwerp.
Three arrests were made as a result of the operation.
Horne said the size of recent seizures shows the threat from drug trafficking is serious, fueling violence and exploitation.
"NCA officers on the front line lead the fight against the serious and organised criminals who chase profits while dominating and intimidating communities," he said.
"However, reducing UK demand for illegal commodities such as heroin requires a systematic response across multiple sectors, including health and social care, prisons and education."