By FOX News Radio's Simon Owen in Belfast, Northern Ireland

Belfast was looking its best when I arrived in the Northern Irish capital this week: it was a crisp winter's day, the sun was shining, and, downtown, a jazz band was playing noisily on the street as people bustled around. All seemed well.

But it wasn't.

Courtesy: AP Photo/Paul Faith/PA Wire

The previous night, Belfast had been hit by a sixth consecutive evening of rioting, with protesters attacking police with everything from Molotov cocktails to golf balls.

They were rioting over a flag.

This violent flare-up began in early December after lawmakers voted to reduce the amount of time the British flag is flown from the top of Belfast City Hall. Whereas previously it flew every day, it'll now only be hoisted on 18 designated dates each year.

That's left some pro-British unionists furious.

Courtesy: Courtesy: AP Photo/Paul Faith/PA Wire

I arrived in Belfast on the first of those dates: the birthday of the Duchess of Cambridge (also known as Kate Middleton).

As I reported from outside City Hall, with the flag behind me, a few people called out as they passed: "It's a disgrace", shouted one taxi driver. "It's good to see our flag back", said another man.

There is support here for the right of those offended by the flag decision to protest. But the rioting is condemned by almost everyone. For many, it's an unwelcome reminder of Northern Ireland's long and bloody bad times. "We lived through the Troubles", local Lesley told me, "and I wouldn't like to see it go back there".

I think it's fair to say that much of the world thought Northern Ireland's problems had gone away. The Peace Accord of 1998, helped along by President Clinton, settled arguments over Northern Ireland's sovereignty (it remains part of the United Kingdom). It was a pact designed to bring an end to more than 30 years of violent conflict. And, 15 years on, Northern Ireland is largely peaceful.

But underlying tensions have never completely gone away. Belfast is still a divided city. In many areas, Protestants and Catholics live apart, and there are large murals, often covering the whole of the side of a house, highlighting the divide through images and slogans.

Among some here, particularly young people, there's concern about the damage the rioting is doing to Northern Ireland's image internationally.

2013 is set to be a big year for the province: among other events, President Obama is due to visit with other world leaders for a G8 Summit in June. But right now, news broadcasts around the world are showing ongoing battles on Belfast's streets.

A college student, George, told me: "It's just annoying. It's embarrassing for the country. It's such a backwards thing to be fighting over."


Courtesy: AP Photo/Paul Faith/PA Wire

But protesters say this isn't just a complaint about a flag; about one decision.

Those demonstrating are unionists: supporters of Northern Ireland's position as part of the United Kingdom. They're traditionally Protestant, and Northern Ireland is traditionally a Protestant country. But recent census results reveal that is changing rapidly, and in Belfast, there's now a Catholic majority.

Various aspects of life, including the flying of the City Hall flag, have been altered to reflect the changing make-up, and the unionists protesting see the flag decision as the final straw. Protest organizer Willie Frazer says they feel their sense of British identity is under attack: "This is not simply about the flying of a flag", he says, "This is about the continuous attack on our British culture, chipping, chipping, chipping away at everything that's British."

The challenge for lawmakers is to listen to their frustrations and try and find a political solution.

Until that happens, unionists are promising Belfast's protests will continue.

LISTEN to FOX News Radio's Simon Owen reporting from Belfast: