A drugs boss hid up to £4.5m of cocaine inside gas canisters.
Gary Morris was snared in July 2020 after a large-scale probe.
The 41-year-old ran a network of couriers to ferry the drugs and also arranged safe houses in a bid to keep them away from police.
Morris kept in touch with trusted associates using encrypted mobile phones.
He even sent a ‘selfie’ to one which helped pin him to the trafficking.
On Wednesday, Morris pled guilty to being concerned in the supply of cocaine at various addresses in Glasgow, Lanarkshire and Midlothian between September 2018 and March 2020.
The builder had been on bail, but was remanded in custody by judge Lord Summers.
The High Court in Glasgow heard Morris was held as part of the Operation Demolish police probe.
Prosecutor Erin Campbell said: “As a result of surveillance and investigations, police identified safe houses used to store and adulterate cocaine in Glasgow, Blantyre and East Kilbride.
“The drugs were being delivered into the safe houses concealed with gas canisters, then adulterated before being handed over by couriers to third parties.”
Those involved were working “under the direction” of Morris – said to be at the head of a crime “sub group” in the central belt of Scotland.
Ms Campbell said the often high-purity drugs found had a wholesale value of £1.5m.
The advocate depute added the cocaine “potentially” could be sold for three times that sum as it goes down the supply chain.
A series of raids occurred which resulted in a number of individuals already being jailed for between four and nine years.
This included police swooping at a safe house in Rutherglen, South Lanarkshire.
Ms Campbell said: “Two men arrived in a van and had two heavy gas canisters, which they struggled to carry.
“Just over an hour later the two were seen to leave again carrying a gas canister each, but they appeared to be much lighter.”
One of the men was stopped during a separate raid in Wishaw, North Lanarkshire.
He was found with a canister, which was dismantled and £80,000 of cocaine was discovered stuffed inside.
Also during the probe, police seized encrypted phones designed to thwart detectives.
Associates referred to Morris, of Carluke, Lanarkshire, as “G” or “Gaz’s driver”.
Ms Campbell said: “A text exchange with a contact stored as ‘G’ in one of the phones involved the user sending a selfie photograph.
“That photo was of Gary Morris.”
Morris was also recorded in prison calls to associates speaking about drugs.
Lord Summers deferred sentencing until next month in Edinburgh.
Morris also faces a separate hearing under the Proceeds of Crime Act.