British border officials have seized around five tonnes of cocaine, with a street value of some £400 million ($540 million), at one of London’s main port terminals, the government said on Saturday.

The drugs were uncovered in a series of operations at London Gateway port in February and March, with the largest single haul, of almost 2,800 packets hidden in a banana shipment, weighing in at around three tonnes.

“The smugglers had gone to extreme lengths to avoid detection — trying to replicate the exact shape and weight of banana boxes to conceal the drugs inside, among fruit in a single shipping container,” the Home Office said in a statement.

Another £80 million worth of cocaine — a tonne in weight — was found last month in a shipping container carrying South American wine.

The Home Office — Britain’s interior ministry — said almost 150 tonnes of illegal drugs were seized by the Border Force in the year ending in March.