A man has been sentenced to 11 years and seven months in prison after pleading guilty to conspiracy to supply controlled drug spice into prisons, being concerned in the supply of heroin and cocaine, and possession of criminal property.

The conviction of Dennis Obasi, 27, of no fixed abode, follows an investigation by the South West Regional Organised Crime Unit (SWROCU) and the Metropolitan Police Service supported by UK Border Force, HMPPS, and three local forces – Avon and Somerset Police, Wiltshire Police and Thames Valley Police.

While an inmate at HMP Peterborough and after his release, Obasi conspired with then girlfriend Emily MacArthur, 31, previously of Charlotte Square, Trowbridge, to smuggle drugs into prisons including HMP Peterborough and HMP Bristol. The pair used fake stamps to produce bogus confidential legal letters coated with spice, concealed drugs within packages for prisoners, and used prison visitors to smuggle the drugs inside.

MacArthur has pleaded guilty to conspiracy to supply spice into prisons, as well as importation of class A drugs, but was not sentenced alongside Obasi as she is currently wanted by police after failing to appear at Swindon Crown Court earlier this year.

The investigation into Obasi and MacArthur began when officers from UK Border Force stopped three separate parcels, all sent from Jamaica, which were addressed to MacArthur at addresses in Frome and Bristol. They were all found to contain cocaine.

Officers from SWROCU and the Metropolitan Police Service carried out a warrant at MacArthur’s Trowbridge flat in February 2020 where both her and Obasi were arrested. Evidence there showed it was being used to produce spice in substantial quantities, with £50,000 worth of spice powder, 116 sheets of paper soaked in spice – worth £48,000 or more in prison – a box containing six bottles of acetone, and 1.86kg of marshmallow leaves seized. Also found were seven fake stamps, piles of envelopes and further letters.

Following Obasi’s arrest, officers found nearly 23,000 messages between him and MacArthur on Obasi’s mobile phone, many of which focused on how to successfully smuggle drugs into prisons.

Police Constable Alex Furniss from the Metropolitan Police Service, said: “The messages, seen as part of the investigation, showed that Obasi would supply MacArthur with names and prisoner numbers for those who wanted to receive or were prepared to accept spice-infused letters.

“The messages also showed lengthy exchanges about the methods being used by MacArthur to make spice, plus their desire to make large profits from their enterprises, including working more closely together once Obasi was released from prison.”

Less than a month after Obasi’s release, he became involved in county lines drug dealing, recruiting vulnerable people to act as drugs runners from a flat in Bath Road, Bristol and later in Abingdon, Oxfordshire. More than £5,000 worth of crack cocaine and heroin and £6,000 in cash was seized as part of that investigation.

In Abingdon, officers discovered a ‘cuckooed’ address – where the home of a vulnerable drug user is taken over by drug dealers usually through intimidation or threats of violence – and two boys aged 14 and 17 working as drugs runners. Obasi had purchased a train ticket from London to Bristol for one of the boys the previous day.

DCI Charlotte Tucker from SWROCU said: “Today’s sentence reflects a huge amount of work by our teams and the Met, supported by our partners, to bring Obasi to justice.

“His offending shows his willingness to exploit anyone, in any way, in pursuit of his own profits, regardless of the exploitation and harm that has caused. The guilty pleas are testament to the strength of evidence we collectively gathered against him.

“Emily MacArthur has also pleaded guilty to conspiring with Obasi to supply spice into prisons as well as importing cocaine. The messages between them show their shared drive to make money. She, too, needs to be brought before the court and I hope that people will come forward with information to help us do just that.”

Prisons and Probation Minister Damian Hinds said: “This sentencing highlights the tireless commitment of our hardworking prison staff and police to cracking down on drugs behind bars.

“Drugs such as spice make it more difficult for us to rehabilitate offenders and cut crime which is why we have invested £125 million to keep our prisons secure and drugs out.”