These pills were marketed and sold under the radar to compete with Ecstasy, a Class-B drug, in the Auckland dance and nightclub scene.
Chase claimed he thought the pills were legal as 4-MMC was not specifically banned under the Misuse of Drugs Act.
However, a covert police investigation, Operation Ark, targeted London Underground and Chase was among 23 people arrested in November 2011.
The police alleged the London Underground tablets were not legal and in fact were analogues, or "substantially similar" in molecular structure, to illegal drugs.
Name suppression has lapsed for Chris Chase more than six years after he was arrested in Operation Ark. Photo / Richard Robinson
This was part of a worldwide phenomenon where chemists were tweaking the chemicals to skirt the boundaries of the law, the police alleged.
Testing also revealed the powders London Underground thought was mephedrone, or 4-MMC, was in fact methedrone, or 4-MEC.
Nearly 255kg of powder was imported over an 18 month period; enough to make almost 1.3 million tablets.
The profits were enormous, with each pill costing around $1 to make.
London Underground sold them, at wholesale, for between $17 and $23 a pill.
Chase maintained his innocence, pointing to legal advice he received, at a High Court trial in 2015 which ran for 18 weeks.
The jury decided both 4-MMC and 4-MEC were "substantially similar" to methcathinone, a Class-B drug, which made them analogues.
Analogues are considered Class-C drugs and in sentencing Chase to 10 years in prison, Justice Peter Woodhouse said the street value of pills sold was nearly $50 million.
The jury found 4-MMC and 4-MEC are analogues of methcathinone, a Class-B drug. Photo / Supplied
"This was the largest Class-C drug importation and dealing operation that has come before the New Zealand courts," said Justice Woodhouse, "and the largest by a very long way."
"Your role in this offending was pivotal ... London Underground, at least in New Zealand, was you."
The Herald can now reveal Chase was also charged with other analogue offences, using different powders from China, while on bail for Operation Ark.
He pleaded guilty to 7 charges of importing a controlled drug, as well as charges of conspiracy to import, possession to sell, and selling Class-C drugs.
His lawyer Ron Mansfield quoted lyrics from a hit by The Clash - "I fought the law and the law won"- in reference to his client.
He said London Underground was one of a number of companies selling compounds which were not specifically listed in the Misuse of Drugs Act.
Chase had sought legal opinions from three lawyers, said Mansfield, and Chase was confident in his interpretation of the law.
While this was arrogant, Mansfield said this is why Chase did not believe the drugs to be illegal -despite being arrested in Operation Ark - and offended while on bail.
However, this was considered to be an aggravating factor in the sentencing hearing.
2010: Police start Operation Ark to investigate pills mimicking Ecstasy.
2011: Chase among 23 arrests from Operation Ark. Police claim 4-MMC and other compounds are not "legal highs" but analogues – or "substantially similar" in structure – to illegal drugs.
2012: Chase arrested, while on bail, for importing new compounds like alpha-PVP in Operation Greenstone.
2015: Jury finds Chase and others guilty of 69 charges of importing and selling Class-C drugs. The verdicts mean 4-MMC and 4-MEC are analogues.
2016: Chase appeals the findings, which puts all connected trials on hold. Court of Appeal upholds convictions.
2017: Chase appeals to Supreme Court but findings are upheld. Supreme Court decision means defendants in connected Operation Ark and Greenstone trials start pleading guilty.
