A boss of the Kinahan organised crime group and two of his key members have admitted a ruse to create an arms cache to help him secure a lighter prison sentence.

Irish national Thomas Kavanagh, 57, was said by the National Crime Agency to be a high-ranking member of the Irish network involved in drugs supply, firearms and money laundering, and acted as the figurehead of the organisation in the UK.

He lived with his family in a fortified mansion, complete with reinforced doors and bulletproof glass, in Tamworth, Staffordshire, from where he ran his criminal empire, the NCA has said.

In 2020 he had been in custody facing a lengthy jail term for trafficking cocaine and cannabis into the UK.

He hatched a plot to fool the NCA and secure a reduced sentence by pretending to help them uncover an illicit stash of weapons.

He enlisted others, including his brother-in-law, Liam Byrne, 44, from Dublin, and Shaun Kent, 38, from Liverpool, to help.

They amassed a haul of 11 firearms, including three Skorpion submachine guns, three Heckler and Koch, an Uzi submachine gun and ammunition from the UK, the Netherlands and Republic of Ireland.

Kavanagh had hoped the ruse would lead the NCA to commend him for helping them and look favourable to the court.

But the plan was foiled after French police smashed the secure encrypted EncroChat communications system in April 2020, and passed information on to the NCA.

Kavanagh had first approached the NCA in December 2020.

He went on to claim in an interview in April 2021 that he had intelligence about an arms cache of between 10 and 20 weapons, said to have come from Holland.

Through his solicitor, he provided a map with instructions and X marking the spot in Newry, Northern Ireland.

The Police Service of Northern Ireland, assisting the NCA operation, went to a farmer’s field, and up a bank, where they found buried, just beneath the surface, two holdalls containing the guns and ammunition.

At the time, the NCA said the guns were in good condition and ready for use.

Having reviewed the EncroChat data in greater detail, the NCA concluded Kavanagh’s tip-off was a put-up job and withdrew its co-operation.

In March 2022, Kavanagh was sentenced to 21 years in prison at Ipswich Crown Court.

NCA investigators had linked Kavanagh and others to large scale drug shipments worth around £30 million at UK street value, as well as movements of cash and firearms.

Kavanagh, Byrne and Kent were about to face trial at the Old Bailey, but pleaded guilty to a string of charges at the 11th hour on Wednesday.

All three admitted two charges of conspiring to possess a prohibited weapon, and two charges of conspiring to possess prohibited ammunition, between January 9 2020 and June 3 2021.

Kavanagh and Kent also admitted conspiring with others to pervert the course of justice.

The charge said that they plotted to “possess firearms and thereafter to hide them and then reveal their whereabouts to the National Crime Agency to enable Thomas Kavanagh to receive a reduced sentence on Operation Hornstay with intent to pervert the course of justice”.

Judge Philip Katz KC said he would sentence the men on October 21 and remanded them into custody.