Three dealers who recruited vulnerable teenagers to act as couriers to run drugs to coastal communities have been jailed for offences of modern slavery in a landmark case.

Glodi Wabelua, Dean Alford and Michael Karemera, all 25, are believed to be the first to be charged under the Modern Slavery Act in respect of recruiting six youths aged 14 to 19 to traffic crack cocaine and heroin to Portsmouth for their “county lines” network.

The trio ran lucrative drug lines – hotlines to buy narcotics – to addicts in the Portsmouth area between November 2013 September 2014 and used the victims to carry the goods to the coastal city and carry cash back to London.

The victims – three girls and three boys – would sometimes be forced to stash drug packages in their body cavities, and would have upwards of £2,000 in cash to deliver to their gang masters in London.

Couriers were housed in squalid conditions in the homes of local users during their stay – often with needles and drug paraphernalia left lying around – and would receive instructions from the defendants via mobile phone on where to sell or drop off the drugs.

They had to ask permission to use any of the proceeds from the drugs to buy food, and were not allowed to return to London until all the drugs had been sold.

Wabelua, of Tottenham, was convicted of one count of trafficking under the Modern Slavery Act at Inner London Crown Court on April 17.

Alford, of Canterbury, pleaded guilty to three counts of trafficking midway through trial while a fourth charge was left to lie on the file.

Karemera, of Lewisham, also pleaded guilty to one like charge midway through the trial. They have been jailed for a total of 12-and-a-half years.

The Met’s anti-gang Trident unit launched Operation Pibera involving 250 officers when the offences first came to light in the spring of 2014, when five of the six victims were arrested in Portsmouth by Hampshire police.

Although several of the victims were initially prosecuted in the youth courts for supplying class A drugs, officers investigating county lines drugs operations later began examining the level of threats and coercion they had been subjected to.

The sixth and oldest victim – who is classed as a vulnerable adult because of a learning difficulty – came to police attention when his outreach worker became concerned he was being exploited.

At trial, he told the court that when a user stole £100 in cash and £100 worth of drugs from him, associates of Karemera staged a mock execution to terrify him into promising to return the money.

He was stripped naked and had a gun placed in his mouth, the court heard.

The five remaining victims refused to provide statements to police, and instead detectives pieced together the case against the three men using DNA evidence and mobile phone data.

Jailing Karemera for five years, Alford for four and Wabelua for three-and-a-half years on Tuesday, Judge Usha Karu said: “One of the main reasons (the victims) were chosen was because of their youth, many were arrested for possession with intent to supply and thus they too became embroiled in the justice system.

“The level of psychological harm they may have suffered is hard to gauge.

“For children who are vulnerable it is quick and easy money – the fact that they consented is plainly no defence.”

She added: “Text messages (on the victims’) mobile phones showed the level of control exercised by you.”

Judge Karu said the victims’ vulnerability made it less likely they would report their exploitation to the authorities.

Some of the drugs hotlines received between 200 and 300 calls a day from users placing orders.

Alford, Karemera and Wabelua would often meet the victims at night to re-supply the drug lines and to arrange individual drug deals on the streets of Portsmouth.

Each line had its own name to ensure users knew who the message was from, even when the number had changed – Alford ran the “Duffy” line, Karemera ran the “Mitch” line and Wabelua ran the “Fly” line.

The defendants were first arrested between September and October 2014, and were initially charged with conspiracy to supply class A drugs and human trafficking.

The drugs supply offences were dealt with first, and resulted in all three men being convicted of conspiracy to supply crack cocaine and heroin in February 2016 at Woolwich Crown Court.

Alford was jailed for 11 years, Karemera for 10, while Wabelua received six years eight months after an early guilty plea.

Their trial for human trafficking to run their drugs empire concluded in April 2019.

The sentences received on Tuesday will run concurrently to their previous sentences for conspiracy to supply class A drugs.

The three men were also barred from owning more than one personal mobile phone or computer upon their release, with all the details of their personal electronics to be registered with police.

They were also banned from providing or arranging transport for anyone under the age of 18 except family members whose parents or guardians had knowledge of the defendants’ convictions.

Earlier this year, the National Crime Agency revealed there were around 2,000 known county lines operations – up from around 750 suspected similar operations the year before.

An operation in January saw NCA officers seize £200,000 in cash and refer more than 1,000 suspected modern slavery victims – of which 600 were children – to safeguarding services.