By Henry Vaughan, Press Association
A Royal Marine with links to dissident republicanism made 14 pipe bombs - four of which were deployed in Northern Ireland, a court heard.
Ciaran Maxwell, 31, compiled a library of terrorism documents, bought chemicals and components and went on to manufacture explosives and devices, which he stashed in purpose-built hides in England and Northern Ireland.
The 31-year-old, of Exminster in Devon, also had maps, plans and lists of potential targets for a terrorist attack - as well as images of an adapted Police Service of Northern Ireland (PSNI) pass card and a PSNI uniform.
The serviceman, who is originally from Larne in Co Antrim, pleaded guilty at the Old Bailey to preparation of terrorist acts between January 2011 and August last year, possessing images of bank cards for fraud and possessing cannabis with intent to supply, in February.
At the beginning of a three-day sentencing hearing at the same court, prosecutor Richard Whittam QC, said: "Across 14 of the locations involved in the investigation, Mr Maxwell had in his possession, or had constructed, 14 pipe bombs."
He added: "Of those 14 pipe bombs constructed by Mr Maxwell, four have been deployed in Northern Ireland."
The court heard dissident republicans have carried out more than 160 terrorist attacks since 2010, involving tactics including the deployment of improvised explosive devices (IEDs) such as pipe bombs.
Mr Whittam said: "Whilst attacks are mainly directed at members of the police, military and prison service, the nature of the attacks leaves members of the public at risk.
"All of the groups remain persistent in their intention to kill and seriously injure."
The court heard Maxwell was a serving Royal Marine Commando at the time of the offences, having enlisted on September 27 2010.
He joined 40 Commando at Norton Manor Camp in Taunton the following year as a rifleman, undertaking some duties in the United States.
Maxwell, who has been discharged from the Marines, was also deployed in the UK - but never in Northern Ireland, said Mr Whittam.
"Between 1 January 2011 and 24 August 2016, Mr Maxwell researched the manufacture and construction of explosives, acquired the items he needed to make explosive devices and constructed the devices," he said.
"He stored the items he needed to make the devices, the devices themselves, ammunition, weapons, tools and resources in hides across England and Northern Ireland.
"He engaged in research to create of a library of maps, plans and lists of potential targets for a terrorist attack."
Along with the 14 pipe bombs, Maxwell also stashed two anti-personnel directional mines, two explosively formed projectiles (EFPs), 29 complete firing systems, 33 initiators - including two military initiators, 13 military "Igniter Safety Fuze Electric" initiators, three fully constructed improvised detonators and other components parts for IEDs.
The court heard he had hoarded more materials and chemicals to make explosives, as well as a replica handgun and ammunition.