Cocaine 'additives' targeted in drug war
9 August 2010 Last updated at 09:18 BST
Police say they are making a large dent in profits made by drug dealers by cracking down on the substances used to dilute or "cut" cocaine.
Pharmaceutical drugs benzocaine and lidocaine are legal substances which cost around £10 a kilo.
But it is illegal to supply them to the underground drugs trade, where they are often mixed with cocaine to make a dealer's supply more profitable.
Daniel Sandford reports.