Two friends who masterminded a £450,000 drugs conspiracy involving a drug stronger than heroin have been jailed for more than 18 years.

Huddersfield computer programmer Aarron Gledhill helped university friend Ross Brennan import the potent Class A drug fentanyl - considered to be as much as 100 times more potent than heroin - before selling it on the dark web.

The pair made vast profits from the three-year scheme, operated from Brennan’s flat in York.

A judge described Brennan as a “sophisticated and arrogant 21st century criminal” as he jailed the pair on Monday.

Aarron Gledhill, from Huddersfield, involved in the £450k drugs conspiracy

Brennan conspired with Gledhill, 30, of Almondbury Bank, Almondbury , to set up an online supermarket for selling fentanyl - an opiod painkiller which has been blamed for hundreds of deaths - alongside other drugs from around the world.

Brennan used encryption software to hide the criminal transactions during their offending which spanned between November 2013 and September 2016.

The substances were posted to 4,000 customers worldwide who left reviews on the now closed down site AlphaBay, trading in online currency Bitcoins.

Brennan received Bitcoins worth between £275,000 and £1.5million depending on fluctuations in the currency’s value, with the average value of their profits around £450,000, a sum spent lavishly.

Drugs found stored in a fridge during searches on Brennan and Gledhill

A court heard Brennan told a friend he was selling hundreds of bags of drugs “in his sleep” and a raid of his flat in Huntington, York, in September last year unveiled tens of thousands of pounds’ worth of drugs and mixing equipment.

The 27-year-old was arrested at a flat in Great Northern Street, Huddersfield, where officers found even more drugs.

During the searches, police also seized a Chemistry for Dummies book, address labels, bags of cutting powder, a mixing machine, a microscope, a set of scales and a number of packages from around the world. Computers and other digital devices were also seized.

The searches led officers to Gledhill, who was later arrested at his home in Almondbury.

Package of Diclazepam drugs seized by police

York Crown Court heard how Brennan had hinted in a Skype chat to a friend he knew the drugs had fatal consequences, saying: “I know there are bodies out there on me… if u do thousands n thousands n thousands… you cant help but f*** up one time maybe [sic]”.

The huge scale of the investigation revealed three of the pair’s customers had died, although it’s not clear whether their deaths were linked to the substances they were sold.

Brennan was jailed for 13 years and eight months for his part in the conspiracy after pleading guilty to conspiracy to import and supply class A drugs and money laundering. He also admitted making and distributing indecent images of children which were found during forensic examinations of his computer.

Gledhill received four years and seven months after also pleading guilty.

Ross Brennan, who masterminded the drugs scheme along with Aarron Gledhill

The case is believed to be the first of its kind in the UK.

Det Insp Nichola Holden, who led the investigation for North Yorkshire Police, welcome the lengthy sentences.

”Every single one of the thousands of transactions could have put lives at risk,” she said. “At one point Brennan recognised that his actions may have led to fatalities. Rather than act on this, he continued the conspiracy to fund his extravagant lifestyle.

“There’s been a lot of recent media coverage about the devastating effects of fentanyl. It’s an extremely dangerous class-A drug. It’s up to 100 times stronger than heroin and even a tiny dose can stop someone’s heart almost instantly.

“I’m confident that Brennan in particular had no doubt about the potential consequences. He was just too greedy, devious and calculating to stop.”

North Yorkshire Police are now preparing an application under the Proceeds of Crime Act to recover to money generated by Brennan and Gledhill.