Scott McSeveney, 37, masterminded the cross-border plan and enlisted HGV company owner Steven Lawson, 48, to transport the haul of Class B drugs from Spain.
But the scheme unravelled when Lawson was stopped by Border Force officers, working on behalf of National Crime Agency and Police Scotland officers in the Organised Crime Partnership Scotland, on the return journey at the Eurotunnel port in France after they found an anomaly in his load.
They then discovered 159 packages of cannabis with a combined weight of 155kg in boxes labelled as watermelons.
At the High Court in Glasgow, McSeveney, of Shotts, Lanarkshire, was jailed for five years and two months after he admitted being concerned in the supply and sale of controlled drugs.
The charge was aggravated by a connection to Serious Organised Crime.
Lawson, also of Shotts, was imprisoned for five years after he was found guilty following a trial at the High Court in Glasgow of being concerned in Serious Organised Crime between April and July 2020.
Both accused were made subject of Serious Crime Prevention Orders which will last three years on their release from custody.
Sineidin Corrins, Depute Procurator Fiscal for Serious Casework at the Crown Office and Procurator Fiscal Service (COPFS), said:
“These two men were integral to an attempt import large quantities of Class B drugs into Scotland.
“But they failed thanks to partnership working between COPFS and the National Crime Agency, Border Force and Police Scotland to disrupt a network of drugs supply.
“These drugs would have caused immense harm. But with these convictions, we have removed them from the streets and made communities safer.
“We will continue to collaborate with our partners as a member of Scotland’s Serious and Organised Crime Taskforce to tackle serious organised crime and this kind of case highlights the extensive work that has been ongoing against these groups.”
The court heard how police surveillance officers saw McSeveney at the offices of MCL Transport in Bellshill, Lanarkshire, a haulage firm owner by Lawson.
Around the same period, he was identified using the encrypted Encrochat platform favoured by criminals discussing ways with associates to traffic cannabis from Europe inside a heavy goods vehicle.
In the messages, he referred to an individual – later revealed as co-accused Lawson - who could drive the vehicle to Europe with a legitimate load and return carrying drugs.
There were also discussions about modifying the vehicle to allow drugs to be imported without detection.
Lawson left Britain in July 2020 and collected the drugs, which were hidden inside 30 pallets of watermelons, from the Spanish town of Benicassim.
But when the lorry arrived at the Eurotunnel border check at Coquelles, France, officers ordered the consignment to be offloaded.
They then uncovered the cannabis hidden inside the pallets of watermelons.
Lawson was arrested and police later also detained McSeveney.
The seized drugs were valued at approximately £604,200, but if sub-divided into smaller amounts, could have had a street value of £1,590,000.
Both men will now be subject to confiscation action under Proceeds of Crime laws to recover monies illegally made.