A man is today in custody after drugs with a street value of around £13 million were found in a warehouse.
On Monday officers from the Met's Central Task Force East stopped an articulated lorry at junction 18 of the A12 near Sandon, as it headed towards London.
There were no drugs inside the lorry but documents led them to an warehouse in Oliver Close, Grays, Essex.
There two pallets were found, loaded with drugs and awaiting collection.
Recovered were 35 kilos of cocaine, 270 kilos of amphetamine and 100 kilos of cannabis.
Tests will be carried out but the drugs are believed to be worth around £13million once sold on the streets.
The lorry driver, aged 40, was arrested on suspicion of being concerned in the supply of drugs and remains in custody at an east police station at this stage.
Acting Detective Inspector Tim Grinsted said: "This significant seizure will prevent a huge amount of drugs from ending up on the streets of London. The Central Task Force will continue to pursue organised criminals that profit from the misery of others."
Enquiries continue to establish where the drugs were due to be delivered to and where they had come from.