Criminals are being hit in the pocket by investigators targeting cutting agents used to reap vast profits from small amounts of class A drugs.
Huge quantities of pharmaceutical drugs benzocaine and lidocaine are being used to bulk up cocaine.
Officers seized two tonnes of benzocaine in just one week after monitoring the underground trade for six months.
The drugs cost around £10 a kilo to buy but can be sold for up to £50,000 a kilo once mixed with often tiny amounts of cocaine.
Investigators swooped on 83 barrels of benzocaine after it was delivered to four customers at Felixstowe sea port and Stansted Airport.
The seizure was the equivalent of one fifth of Britain's annual legitimate use of the drug as a dental anaesthetic and ingredient in medical creams and sprays.
It is the cutting agent of choice for drug dealers because it has a numbing sensation when placed on the skin, like cocaine.
One Serious Organised Crime Agency (Soca) officer said: "These are targeted preventative measures to stop the criminal market.
"We expect this to seriously damage the criminal base and impact heavily on the market.
"It is keeping money out of the trade because they cannot maximise their profits, money that is often reinvested in criminal activity."