Patrick Kielty used to have a lot of fun at the IRA's expense. When the peace process took hold in the mid-1990s, the stand-up comedian from Co Down (whose father was murdered by loyalist gunmen) had a routine in which he mocked Irish republicans' tendency to split into tinier and tinier factions.

"There's so many of them now, isn't there?" he asked his audiences. "There's the Real IRA, the Surreal IRA, the Continuity IRA, the Provisional IRA, the Official IRA, Low Fat IRA, Diet IRA, I Can't Believe It's Not The IRA…"

Today Kielty's joke might not seem quite so funny. Over the last few months there has been a series of security warnings, weapons seizures and suspect arrests, all suggesting that a force calling itself the 'New IRA' needs to be taken deadly seriously. Even more disturbingly, we have seen evidence on our television screens that the old 'Brits Out' mentality remains alive and well in some quarters - just as Brexit is threatening to recreate a hard Border and present terrorists with a 500km target.

Michael Hayes is the sort of republican hard man whose internal war will never be over. Last month, the 69-year-old Dubliner appeared on a BBC documentary and confirmed his membership of the IRA unit that slaughtered 21 people in the 1974 Birmingham pub bombings. As such, he apologised and took "full collective responsibility" for the atrocity - while simultaneously refusing to say which of his comrades planted the devices.

Hayes's motivation for doing this interview is still obscure. If he was stupid enough to think it would give the victims' relatives some closure, he soon realised his mistake.

Their representatives quickly branded him "gutless" and demolished his claim that the IRA had never actually meant to hurt anyone. (Why was the only phone warning ridiculously vague and delivered just six minutes before the first bomb went off?)

They also pointed out that if he had wanted to show genuine remorse, he might have refrained from going on camera while wearing his old combat fatigues.

Hayes's choice of outfit really gave the game away. It reflected some diehards' conviction that anything less than a 32-county socialist republic is totally unacceptable, which makes the Republic of Ireland and Northern Ireland nothing but rogue states. Not only do they see the IRA as an "undefeated army", to quote the T-shirts you can still buy for €19.99 from Sinn Féin's online shop, they also believe it to be the only legitimate security force on this island.

For anyone under 30, Hayes must look like a creature straight out of Noah's Ark. After all, it is almost a quarter of a century since the Provisional IRA laid down its arms and gave Sinn Féin permission to pursue a purely peaceful strategy. Can we not dismiss him as the Irish equivalent of those Japanese soldiers who remained in their jungle hideouts until the 1970s, tragically unaware that World War II had entered the history books long ago? Sadly, the answer is no. While Hayes's generation of gunmen and bomb-makers may be too old to cause any more trouble, their spiritual successors are now firmly in place.

According to Garda Assistant Commissioner Michael O'Sullivan, the New IRA poses a bigger threat than any dissident group over the last 20 years - an assessment also shared by intelligence sources in Northern Ireland and Britain.

The New IRA was formed from a variety of other republican factions in 2012 and is thought to be extremely well-resourced. On June 2 this year, gardaí seized a staggering six kilos of TNT from a taxi in inner-city Dublin, described by one explosives expert as "big enough to blow up a street".

The organisation has roughly 50 activists and 200 supporters, which might not sound like a lot - but in the words of James Connolly, "a pin in the hands of a child could pierce the heart of a giant".

Four suspected New IRA members were arrested by the Special Detective Unit after a series of dawn raids in Tallaght last Wednesday morning. Two have since appeared before a special sitting of the Special Criminal Court. These developments are certainly encouraging - but as long as the 'armed struggle' mindset persists throughout certain communities, Ireland's battle to stamp out political violence will always be a work in progress.

So where does the blame chiefly lie? According to the DUP MP Jeffrey Donaldson, Sinn Féin has created a "political vacuum" in Northern Ireland that allows dissident mobs to thrive. While Gerry Adams would obviously deny this, one awkward fact remains - his party still insists that the Provos' 28-year campaign of murder and mayhem which claimed more than 1,800 lives was morally justified.

In other words, Sinn Féin's new-found commitment to peace is based on tactics rather than ethics. When Martin McGuinness died last March, Adams praised his IRA record by declaring that he was "not a terrorist" but "a freedom fighter".

On his headstone are carved the words 'Óglaigh na hÉireann' (army of Ireland) - a grave insult to the genuine Irish soldiers and gardaí who were killed by IRA bullets.

As we know to our cost in Ireland, however, decommissioning weapons is a lot easier than decommissioning an entire hate-filled philosophy. In his newly published memoir 'First Confession', the British politician Chris Patten describes his experiences as chair of the Independent Commission on Policing for Northern Ireland and expresses his deep love for the place.

"But I was never seduced into thinking that these six counties were so uniquely beautiful as to explain or justify people killing to control them," he writes. "We ruled Northern Ireland because that was what the overwhelming majority of its people wanted us to do, and we will continue to do so until they don't."

It's a message that some republican dinosaurs still seem incapable of getting through their heads.

Irish Independent