The Falls in Rome isn’t like most other Irish bars abroad.

Down a nondescript lane, past the threshold of an unassuming facade and into a dimly-lit alcove, visitors are left to remark upon walls unexpectedly draped with all manner of Irish republican memorabilia including signs with slogans exclaiming ‘Up the Ra’ and ‘Free Derry’, alongside a liberal helping of tricolours and maps of the Emerald Isle.

"I have no more paintings in my house at the moment", quips Fabian Tranni, as he crouches down to display a painstakingly intricate tattoo of a large green harp on his left forearm which he drew himself.

With the help of a couple of friends, he opened the Falls Road Irish Rebel Pub half a year ago, primarily as a hangout spot for members of the Irish Clan Roma supporters group.

A team which came into existence following the forced amalgamation of three local clubs by fascist authorities in 1927, AS Roma's right wing roots sit largely at odds with militant Irish republican ideologies. However, group founder and proud Roman Tranni sees no inherent contradiction, and views his twin devotions as entirely complementary.

“I studied in Dublin for a year in 1994. I fell in love with that country, it was great,” says our host, as we sit down for the obligatory pint of Guinness under an imposing-looking poster of Bobby Sands.

“It started like a joke, we brought an Irish flag to the stadium, then other guys started getting interested in the flag, and started asking us ‘are you Irish?’. They fell in love with Irish people because of their anti-imperialism, and because many Lazio flans are influenced by the English fans, especially during that period in the ‘90s with Gascoigne,” says fervent Giallorossi supporter Tranni, reverting back to the group’s genesis in 1998.

Subsequent trips to Limerick, Belfast and Derry copper-fastened his partisan views on the ‘Irish Question’, as he terms it, and his careful references to the ‘six counties’ and the ‘north of Ireland’ provide further evidence of an acute awareness of the sensibilities which still pervade in that part of the world.

“This year in January, I brought all the new guys from the group to Derry for three days just to show them the meanings of some things they didn’t know, and they could decide if they really like it or not. If they are interested, they can come along and we try to explain why we have the Irish flags and all that stuff.

"We met guys from Shamrock Rovers, they often come to Rome. They join us to watch the match. We've also been in Dublin for matches," he explains, adding that the club's membership has almost exclusively been drawn from local enthusiasts since its inception.

Some Italian sides have enjoyed an enduring and unlikely affinity with Ireland. A gathering of Irish-based Roma fans regularly congregate in Dublin city centre to catch all the Serie A action and, up until recently, teams including Sampdoria and little-known second division outfit Ternana have also accommodated a Celtic contingent within their fan structures.

But none of these connections comes close to resembling the unique and somewhat perplexing relationship which Tranni and his cohort share with our small Atlantic nation.

The timing of my trip last May proved opportune, with city rivals Lazio and Roma set to square up in a season-defining encounter at the Olimpico that weekend at the end of a stuttering campaign for both sides (they finished third and second on the ladder respectively).

Off the pitch, Italian football in general has been beset by a legacy of crowd trouble, with the Derby della Capitale proving particularly problematic over the years with weapons seizures, hospitalisations and fractious scenes on the terraces a frequent occurrence before big matches.

As news begins to filter through that two fans have been stabbed on the way into the game (the aftermath of which saw dozens of disgruntled Lazio fans tear-gassed by police), I cast my mind back to Tranni’s assurances that the Irish Clan Roma is a fairly moderate group compared to other, more belligerent sections of the away side’s support.

Its numbers have dwindled in recent years, with many of his fellow founding members choosing to put down the Clan’s trademark green, white and orange flags and move away from the raucous environs of the Curva Sud- home to Roma’s renowned and, at times, infamous ultras supporters- as they get older.

Our guide is eager to dispel any notions that drug-taking and stabbing attempts- practices said to be commonplace among some younger Curva Sud regulars- are tolerated among more mature and respectable ultras, many of whom remain partial to the odd pre-game dust-up nonetheless.

“There are no guys in our group who use cocaine, and that’s a great thing. And that’s very dangerous because if you find people who are high on drugs you can’t speak with them.

“They are groups of three or four, they move around… they might follow you because they recognise you are not Italian, and they’ll stab you. I don’t know why, and I don’t like it but it happens.

“The older ultras of the Curva Sud are starting to do meetings with them to explain the way to be ultras. It’s not that. You have to sing a lot- all 90 minutes, you have to have colours.

Despite these warnings, he fondly reminisces about a more “honourable” encounter between opposing factions ahead of the Champions League visit of CSKA Moscow last year.

“It was a great thing in my opinion, because it was 50 Russian guys against 50 or 60 of us and we kicked and punched for 15 minutes but that’s all, nobody stabbed. That’s the way to be ultras in my opinion.

“In that occasion, nobody was banned from that stadium. We fought in front of stadium, there were no police and they didn’t care. If it happens that you meet the other groups and you want to fight you can do it, but in that case there is a way to do it.”

Approaching the ominous-looking security cordons surrounding the Olimpico on match night, one gets the distinct impression that the authorities are taking no risks in order to avoid a repeat of any such violence before the game.

After having their tickets inspected against a form of ID a few hundred metres from the ground, fans then file through a set of automatic turnstiles before they are confronted by another squadron of luminous jackets who repeat the cross-checking ritual and perform a gentle pat-down.

A matter of yards away, armed riot police are ready to give prospective attendees another, more thorough inspection of their person, bags and shoes, after which entry is finally permitted.

Going through the same routine prior to kick-off, I take a moment to steel myself for the impending sensory assault before scaling the steps of the famous stand.

Inside the stadium, the unmistakable waft of sulphurous flare fumes combines with the thunderous boom of fire crackers to create a foreboding spectacle as Rome’s bitter nemeses prepare to do battle.

Perched among the Roma fans, it’s easy for a clueless visitor to get swept up in the rhythmic clapping and chanting of the ultras- a relentless din which lasts the whole 90 minutes- as huge flags flutter back and forth to the front of the stand.

Fortunately for Tranni and his companions Rudi Garcia’s men produced the win which gifted the legions of Giallorossi faithful a guaranteed second place finish in the league, along with a feeling of elation that only a crucial win over age-old enemies can bring.

A show of reciprocal admiration between 'Il Capitano' Francesco Totti and his legions of adoring followers in the Curva Sud provided a fitting farewell photo op ahead of my trip back to Piazza Flaminio in the city centre, where ecstatic motorists feverishly beeped their horns and waved flags and scarves bearing the victors' colours into the wee small hours of the morning.

Months later, promising pre-season performances against the likes of Man City and Real Madrid coupled with a raft of new signings including Arsenal netminder Wojciech Szczesny and Chelsea's Mohamed Salah (both on loan) indicate that Roma will be well-equipped to challenge for top domestic honours in 2015/16.

Tranni’s appraisal of the season gone by is tinged with regret- “We have a good team... but something broke.” Still, as is his right in the Eternal City, the Irish Clan’s chieftain remains eternally optimistic that a return to the glory days of the early 2000s may be just around the corner, and you get a sense that he will keep the green flags flying high over the sea of crimson and gold for some years to come.