How gardaí foiled threats by dissidents around two Royal visits
Events overseas over the past few years forced the gardaí to focus much of their anti-terrorist attention and resources to confront the threat posed by international jihadis such as Isil.
Behind the scenes, however, there was no pulling back by the Special Detective Unit and other specialist units in combating the possible resurgence of dissident republican groups.
Earlier this year, during a display of weaponry and explosives seized from dissidents, the assistant commissioner in charge of crime and security, John O'Mahony, issued a warning that the threat dissidents posed was as serious as ever.
He highlighted the growing sophistication of their "engineers" as they aimed to develop their technical capability.
The significance of that threat has been underlined in two cases finalised in the Special Criminal Court in the past month. Details emerged of sinister attempts to mount deadly attacks during the State visits of Queen Elizabeth five years ago and Prince Charles last year.
The capture and subsequent jailing of Donal Ó Coisdealbha (25) dealt a major blow to the "engineering" skills of the Real IRA.
Ó Coisdealbha, from Killester, on the northside of Dublin, is a relative of former leading Provisional IRA bombmaker Jim "Mortar" Monaghan, who became known in later years as a member of the Colombia 3.
Ó Coisdealbha was arrested by the Special Detective Unit six days before the visit of Prince Charles and Camilla after coming to the attention of detectives during an investigation into dissident activities.
He was placed under surveillance and seen meeting convicted IRA members in two Dublin pubs as well as acting suspiciously at the rear of Glasnevin Cemetery.
He was also seen buying cling film, and driving to a house in Wexford. During a search of the house, four improvised rockets, a booster tube, five phones, Semtex and homemade explosives, a timing power unit (TPU), broken circuit board, cortex wire and two detonators were found.
In a follow-up search of his locker at NUI Maynooth, where he worked in biomedics, gardaí also discovered another TPU and a broken circuit board.
Garda evidence was given that it was clear from recorded conversations about a motorcycle and detonators that preparation was well advanced for a bomb attack - and officers believed it was to take place around the time of Prince Charles's visit.
Three TDs, Maureen O'Sullivan, Mick Wallace and Clare Daly, were among seven proposed independent sureties on his bail application, but it was refused. Ó Coisdealbha later pleaded guilty to membership of an unlawful organisation and was sentenced to five-and-a-half years in jail.
Then, earlier this week, Dubliner Donal Billings (66), with an address in Drumlish, Co Longford, was jailed for eight-and-a-half years after he was found guilty of possessing an explosive substance at Longford railway station car park on May 16, 2011.
Billings's plan was to cause serious disruption to preparations for Queen Elizabeth's visit by planting a bomb on a bus and following up with a series of hoax telephone calls.
One of the calls claimed that two mortars were due to explode at Dublin Castle during the State banquet for the queen.
All of the calls had to be treated seriously as the device on the bus, with 31 people on board, was viable and capable of causing death and destruction.
The bomb was discovered in the luggage hold and included gunpowder, a two-litre bottle of petrol, a TPU, battery and a fuse.
If it had exploded, it would have turned into a fireball and seriously injured or killed the bus passengers and the driver.
It is understood the device had also been doctored to create the impact of a blast bomb, posing an additional risk of shrapnel inflicting injuries to the passengers.
Presiding judge Mr Justice Tony Hunt said Billings placed a device on public transport - an "outrageous, highly irresponsible and dangerous act", which "recklessly exposed passengers, staff and members of the emergency services to very significant risk of serious injury or death".
After the discovery, all garda units were placed on high alert and extensive searches were carried out at the other locations where Billings had claimed bombs were planted.
During the initial phone call, it was alleged that a bomb had been planted at the Sinn Féin offices in central Dublin. It was searched, along with another bus.
A further phone call threatened that two mortars were timed to explode at Dublin Castle at 8pm on the evening of the State banquet.
The caller said: "I'm a member of the republican brotherhood, squad A.
"Two mortars are set for Dublin Castle at 8pm. This is for the queen of blood and war of Iraq."
Searches were carried out but nothing was found.
A third phone call warned there were two bombs planted at Cork airport, where Queen Elizabeth II was due to fly out of Ireland. This was also a hoax.
Investigators found that the SIM card for the phone used to make the calls had been bought in an O2 shop in Longford shopping centre and additional information was generated through analysis of mobile phone records and CCTV footage from the shopping centre and the railway station.
Billings, who had two previous convictions from Northern Ireland in 1973 for possession of explosives, was identified as a suspect. He was placed under surveillance and followed from his home in Drumlish to a Lidl car park in Longford, where he was arrested.
In his bag, gardaí found the Sim card and handwriting on the packaging including the phone number for Longford garda station, the registration number of the Corduff bus and the Irish words Cor Dubh.
Officers also seized a phone from Billings and established that its IMEI, a 15-digit unique number used to identify mobile phones, had been used in conjunction with the 086 number.
The phone calls had been made using a mast near Billings's home in Drumlish and they found a bottle of petrol and a makeshift funnel in his car.
The two trials serve as a grim reminder of the dangers that dissidents and their sympathisers, although small in number, continue to pose to the security of the State.