George Thompson, 59, of Livingston, was found guilty under the Misuse of Drugs Act at the High Court in Livingston on Thursday, June, 30.
Police recovered large quantities of cocaine and amphetamine in 2014. On Friday, November 20 that year, the 59-year-old’s Transit van was stopped on the A7 near Heriot village, and a half-kilo of cocaine was found within.
Several addresses in West Lothian, which were linked to Thompson, were subsequently searched resulting in the seizure of three further kilos of cocaine along with dealer quantities of amphetamine.
The total value of the recovered drugs was in excess of £500,000.
Thompson is due to be sentenced on August 5.
Detective Chief Inspector Kenny Gray from the East Organised Crime and Counter Terrorism Unit said: “There is no doubt that George Thompson was heavily involved in the distribution of drugs throughout the Lothians and Scottish Borders, given the significant quantity of Class A drugs we seized from vehicles and properties linked to him.
“The cocaine was of a very high-purity and we are delighted to have recovered it before it could cause untold harm to our communities.
“Tackling drug crime is a priority for Police Scotland and we robustly gather and investigate all intelligence from the public relating to those involved in offences of this nature.
“If you wish to report ongoing criminal activity in your area then please contact Police Scotland on 101 or make an anonymous report via the charity Crimestoppers on 0800 555 111.”