I was driving through Belfast recently and found myself at the lights at the Queen Elizabeth Bridge, just as hordes of Northern Ireland fans were heading for the Fanzone at the Titanic Quarter to watch the European Cup.

I rolled down the window and shouted, “Hey lads, you going to see the game?” A group of them stopped. “Have you heard the bad news?” “No, mate what is it?” I paused, and said, “Apparently Will Grigg is on fire.” They exploded and as I drove off, hundreds of them were singing about the most famous unused substitute in the history of world football.

It used to be all so different. BBC Northern Ireland aired a fascinating documentary recently. It began with footage of the 12th of July parade on Belfast’s Shankill Road in the mid-1960s. As one of the bands passed, belting out "The Billy Boys," a girl of seven or eight turned towards the camera and shouted “Fuck the Pope.”

Here are the words in full:

"Hello Hello (bellowed loudly)

We are the Billy boys

Hello Hello.

"You’ll know us by our noise

We’re up to our knees in Fenian blood (Fuck the Pope)

Surrender or you’ll die

Cause we are the Billy Billy Boys."

The unofficial Northern Ireland supporters’ anthem echoed around Windsor Park since time immemorial. Until the new millennium, you could buy the CD in the Windsor Park shop. But in or around 2000, the supporters’ club store was cleansed of sectarian material and the song was banned.

On October 30, 1992, Loyalist gunmen had walked into the Rising Sun bar in Greysteel, Co Derry where a Halloween party was in full swing. Dressed in balaclavas and boiler suits, no one passed any notice until Stephen Irwin, the lead gunman, shouted “Trick or Treat” and opened fire, murdering eight people, including Victor Montgomery, a 76-year-old Protestant drinking with his Catholic neighbors.

The following year, Northern Ireland hosted Jack Charlton’s Irish Republic team in Windsor Park in a World Cup qualifier. When Jimmy Quinn’s exquisite volley put the home team one up, the stands rocked to chants of ‘Greysteel Eight, Ireland Nil’ and ‘Trick or Treat.’ The experience prompted playwright Marie Jones to pen "A Night in November," a shocking and accurate portrayal of sectarian hatred at the time.

A year after that terrible massacre, in 1993, the first ever religious breakdown of the Royal Ulster Constabulary was published. Of the 13,014 police officers, 6.9 percent were Catholic. I remember consternation in our circles that so many Catholics were working for the enemy. In Dungiven, like other Catholic towns, the police weren’t served in the shops and no one spoke to them, save to call them black bastards or chant, ‘SS RUC.’

Those were the bad old days. Then, suddenly, and I am not sure when this happened, sectarianism was an embarrassment. Like racism, it became something to be ashamed of. I think perhaps the seeds were sown round about the time when Ian Paisley fell under the spell of Martin McGuinness and the two of them went around like shy but delighted lovers.

In 2001, the RUC, a Protestant force for a Protestant people, was disbanded and replaced by a new force called the Police Service of Northern Ireland. When the BBC sent a camera crew to Crossmaglen for a vox pop to ask if the locals would join this new body, Paddy Short voiced the feelings of most of us when he said, “We’re not built that way around here.” That sentiment soon evaporated. As of March 14, 2016, the proportion of Catholics in the PSNI is a whopping 31.2% and rising.

In 2010, my father and I sat with Martin McGuinness at a Derry GAA match in Celtic Park. Before the throw-in, his phone beeped. “Look at this Joe,” he said to me, shaking his head in amusement. It was a text from someone called Peter. The message read: ‘Go on the Blues! You’ll never catch us now.’

The Peter in question was then First Minister Peter Robinson, an avid Chelsea fan. They had just won a vital Premier League game, leaving Martin’s Manchester United trailing in their wake. The title was Chelsea’s to lose. “He’ll torture me now,” said Martin, laughing.

I thought of Martin’s lethal past. With his balaclava and armalite, crouched behind a wall in the Bogside. And I thought of Peter, filled with juvenile bigotry, marching through the streets of Clontibret to claim the town for God and Ulster. Yet, here they were, in 2010, running the country together and ribbing each other about their favorite soccer teams.

The following April I stood in Nuala Kerr’s house in Beragh. Her son Ronan’s coffin was in the small living room, placed against the wall, right under a large portrait of Peter Canavan kicking his famous winning free against Armagh in Croke Park. Mrs Kerr gestured towards the coffin and said to me, “It’s so pointless.” Her son was a PSNI officer. He was blown up by an under-car booby trap bomb as he got into his car to drive to work. I will never forget that butchered boy in his coffin, under the portrait of Peter the Great.

The following Sunday, at Tyrone’s league game in Dungannon, a notoriously Republican town during the Troubles, there was a minute’s silence for the dead boy, led by Mickey Harte and his Tyrone team. Perhaps more than anything, that was the moment.

It is a different world up here now. My kids know nothing about the Troubles. A few of them went to the scouts when they were younger, sang "God Save the Queen" on the Queen’s birthday and came home proudly holding aloft crayon drawings of the bejeweled heiress. The boys’ great-grandfathers would have turned in their graves.

Sectarian assaults used to be a daily occurrence in Belfast. They have all but disappeared. I am a criminal barrister and cannot recall the last time one of those came before the courts. The Shankill Butchers killed countless Catholics, cutting them to pieces with meat cleavers and knives. The only butchers up there nowadays sell a bag of sausages and minute steaks for a fiver.

Just two weeks ago, DUP First Minister Arlene Foster tweeted:

Well done Rep of Ireland. My goodness what a result!

— Arlene Foster (@DUPleader) June 22, 2016
When Arlene was a child, her father, a farmer and part-time RUC man, was unbelievably lucky to survive an assassination attempt by the IRA. In an interview with The Sunday Tribune in 2005, Arlene said, “They shot him in the head as he was closing in the cattle. He came crawling into the house, blood streaming down his face. We couldn’t stay in Roslea anymore. I had to move house and school — it was very traumatic.”

The same day as Arlene’s tweet, her deputy, Martin McGuinness, tweeted:

En route to France,two big games coming up for Martin & Michael O'Neill's teams.Hoping both can advance in #EURO2016,wishing them both well.

— Martin McGuinness (@M_McGuinness_SF) June 21, 2016
Martin told me on Thursday night that when he had arrived at Dublin Airport to get his flight to the games, he was besieged by Northern Ireland fans who queued up for selfies. Martin sat in the stand for the Northern Ireland-Germany game, beaming. Twenty years ago he would have been tarred and feathered for such treachery. Now, nobody gives a damn.

Throughout the Euros, which should have been declared a public holiday North and South, the two sets of fans gathered at the Fanzone in the Titanic Quarter in Belfast for the games, filling it to its 10,000 capacity. There wasn't the slightest bit of bother. Not a “black bastard” or a “Fuck the Pope.” Not a bottle or a punch thrown. Only thrills, laughs, drink, and the Will Grigg song. You may not be aware of this, but apparently he’s on fire. In training . . .

* Joe Brolly is a lawyer in Belfast, a former All Ireland winning footballer with Derry, and a leading commentator on Gaelic football.