Packages found washed up on the UK coast contained almost a tonne of cocaine worth about £80 million, the National Crime Agency (NCA) has said.
The drugs, which were wrapped in waterproof bags and attached to life jackets to make them float, are believed to have originated in South America.
They were discovered on Monday by passers-by who alerted local police, who seized the packages and took them to a secure location.
Martin Grace, NCA branch commander, said: “This is a significant amount of class A drugs which we think originated in South America, but we are keeping an open mind about how the drugs washed up here and where the end destination might have been.
“Clearly though, losing a consignment of this size this will represent a significant hit to the criminal networks involved.”
Two separate consignments of packages were found washed up on beaches near Hastings and Newhaven, East Sussex.
NCA officers are investigating the seizures, which are being linked.
Samples have tested positive for cocaine, though a full forensic examination will be carried out.
The combined weight is thought to be around 960kg, which if cut and sold on the streets in the UK would have had an estimated street value of around £80 million.
Pictures released by the NCA on Tuesday show several packages lying on a pebble beach.
Mr Grace added: “Our investigation is being assisted by both Sussex Police and Border Force, and is also likely to involve international partners.”