A ROYAL Marine who was preparing a terrorist attack is facing a jail term.

Ciatan Maxwell, 31, who served with Norton Manor Camp-based 40 Commando, is appearing at the Old Bailey for sentencing after pleading guilty to preparing for an act of terrorism at an earlier hearing.

The sentencing is due to start today (Wednesday) and is expected to take three days.

Maxwell was arrested in Somerset last August after the discovery of two major arsenals of weapons hidden in Northern Ireland.

Police found a "library of documents" resulting from research about explosive substances, the construction of explosive devices, and tactics used by terrorist organisations.

Maxwell admitted a series of offences, including manufacturing explosives and constructing explosive devices, when he appeared at the Old Baily in February.

Maxwell, of Exminster, Devon, and originally from County Antrim, pleaded guilty to preparing terrorist acts between January 2011 and August 2016.

As well as his hoard of explosives, he also hid ammunition, weapons and tools for making bombs, the court heard.

Maxwell also admitted possessing images of bank cards for fraud and possessing cannabis with intent to supply at his court appearance via videolink, when he was remanded in custody.

Maxwell was arrested last August by officers from the Metropolitan Police Service's counter-terrorism command, supported by Avon and Somerset and Devon and Cornwall Police.

He was arrested in a pre-planned operation believed to have been linked to the discovery of two dissident arsenals in woodland in Larne, County Antrim, in 2016.

Officers searched a house in Exminster in Devon and nearby Powderham New Plantation woods as well as a number of properties in Larne.

Months earlier, two separate hauls of weapons were discovered in Carnfunnock and Capanagh parks.

In March 2016, police said four barrels were unearthed at Carnfunnock - two were empty but two contained a variety of bomb-making components, including wiring, toggle switches, circuit boards, partially constructed timer power units, ball bearings and a small quantity of explosives.

In May, an armour-piercing improvised rocket and two anti-personnel mines were among the cache recovered at Capanagh.

Several pipe bombs, magazines and ammunition for an assault rifle, and bomb component parts and command wires were also concealed in barrels in purpose-built holes in woodland.

The court heard it has been "commonplace" for Northern Ireland-based terrorist groups to conceal bomb-making equipment and other terrorist material in purpose-built hides.

But Mr Whittam said: "In recent history and certainly over the last five years, the number of hides in this case, their geographical dispersal, their attribution to a single person constructing and managing them and the amount of material stored within them, would be highly unusual."

The prosecutor described how a walker stumbled on one of Maxwell's in Carnfunnock Country Park, near Larne, in March last year.

Another was found in Capanagh Forest in Co Antrim in May by someone searching for a suitable place to camp, the court heard.

The court heard that ammunition used by the British Armed Forces was found along with bomb-making materials and IEDs.

Mr Whittam said: "It is our case that some of the items inevitably must have been taken from the UK to Northern Ireland by this defendant and it may be that, when travelling between England and the UK, bearing in mind the identity cards he would have had and his position, his passage would have been easier than others to take items with him."

Maxwell appeared in court by video link from Woodhill prison in Milton Keynes, where he sat at a desk with a laptop and making notes.

The court heard he was being watched by police by the middle of August last year and was repeatedly seen going to and from Powderham New Plantation, near Teignbridge, Devon.

The court heard he looked "shocked" when he was arrested on suspicion of terror offences at his base in Taunton, Somerset on August 24.

From a search of his work locker, officers seized cannabis and hallucinogenic drugs DMT and LSD, while items including hand-written notes were recovered from his Exminster home.

On one, headed "Easter Leave", was written "test pipe bomb" and "recce (of a town in Northern Ireland redacted in court)".

The court heard similar "to do lists" were found in one of 13 hides initially found by police in the Powderham woods.

"Some things obtained, to get, some things to be tested," the prosecutor explained.

From September 2 Maxwell provided police with "extensive information" about further hides and items in Powderham, including a modified torch, which was designed to act as a booby trap, exploding in the hand of anyone who tried to turn it on.

He also told officers about more hides in Northern Ireland, including at the Old Bleach Works in Larne, where he said he had been with his friend Niall Lehd, who told Maxwell he was part of the Continuity IRA.

Among the items found were five pipe bombs and DDNP - a high explosive seen in Northern Ireland for only the second time.

The first example was recovered following an explosion in Larne, after which Lehd was jailed after pleading guilty to possessing an explosive substance with intent to endanger life in 2014.

The court heard the February 2013 blast was one of four pipe bomb "deployments" linked to Maxwell.

A detonated pipe bomb was recovered following an explosion in December last year, while another undetonated device was found against a windowsill of a house in Carnlough.

Components of a fourth pipe bomb were found in Belfast.

The court heard terrorist documents and bomb-making guides, including the Irish Republican Army "Green Book", were found on Maxwell's media devices, along with potential targets for terrorism.

Police found satellite map images of power stations in Northern Ireland and Larne police station with a "blast radius put on top of it".

There were also street maps of military barracks, a council building and an "Orange hall", as well as details of the addresses of HMRC offices in Northern Ireland, the Northern Ireland Office in Westminster and London's NCA headquarters, the court heard.

Other files included the names and contact details of PSNI officers and a police/MI5 officer in the UK, the court heard.

Mr Whittam said: "Whether I was to describe it as attack planning or preparation, it has that hallmark."

The court heard, in police interviews, Maxwell denied any intent to commit an act of terrorism or to kill anyone, claiming he "got in over his head" and was not capable of using the devices.

But he described detailed conversations with Lehd about attack planning and accepted conducting research to compile target lists, the prosecutor said.

He said he and Lehd discussed the placement of hoax devices and secondary live devices to kill police officers.

Mr Whittam said: "Mr Maxwell repeatedly accepted that the devices would be used by others for terrorist purposes.

"For example, he agreed with the statement that the items were made for the Continuity IRA (CIRA) with the intention of attacking police and police stations."