* Disillusioned youths as young as 11 mainly behind riots
* Limited numbers mean few risks to 15-year-old peace
* Politicians powerless to stop damage to N.Irish reputation
* Protestants demographically and economically under pressure
By Stephen Mangan
BELFAST, Jan 10 (Reuters) - Northern Ireland's worst period of violence since a 1998 peace deal ended three decades of conflict has highlighted just how fragile that accord is and raised fears that the province cannot fully emerge from its bloody past.
Petrol bombs and guns returned to the streets of Belfast after a vote by local councillors to end a century-old tradition of flying Britain's flag from City Hall every day provoked pro-British loyalists into riots that have raged for much of the past five weeks.
For locals, it has stirred memories of the 30 years of sectarian conflict that pitted Catholic nationalists seeking union with Ireland against British security forces and mainly Protestant loyalists determined to stay in the United Kingdom.
The police, who are the target of the latest disturbances, say they have contained the unrest and with rioters unable to muster numbers much larger than 200, the threat to the 15 years of peace has so far been limited.
However business has been severely disrupted, Belfast's improving reputation tarnished and some politicians worry that they can no longer get through to those who feel they have no place in a new Northern Ireland where they sense they are both economically and demographically under pressure.
"The politicians have lost control," Danny Kennedy, a member of the province's second largest pro-British party, the Ulster Unionists, and a minister in Northern Ireland's devolved government, told Reuters.
"Twenty years ago when the two leaders of Unionism issued a statement appealing to loyalists to stay off the streets, they would have been obeyed. It's a worrying factor and a new factor in Loyalism - the constituency which says things have gone too far and nobody is standing up for what we stand for."
That constituency is mainly made up of disillusioned teens who, with faces covered by scarves and British flags draped over their shoulders, pelted police with petrol bombs and fireworks for much of the past week.
While police have accused pro-British militant groups of exploiting the violence, the angry crowds have been dominated by younger faces with the disturbances arranged via social media sites like Facebook, much like riots in London in 2011.
Of the 107 people arrested since the trouble began at the beginning of December, police said one third have been under the age of 18 with an 11-year-old boy the youngest amongst them.
"The scary thing is, these kids aren't listening. For a lot of them it's just fun, a game of cat and mouse with police which is better entertainment than their Playstation," said Mark Houston, director of the East Belfast Mission group that is working with protesters to try and quell the unrest.
"They don't have any prospects, there's a hopelessness so you've a lot people involved in recreational rioting, with nobody really with the power to switch it off. They've no fear of anyone and it isn't any one group doing it."
Houston, whose offices are based at the heart of the unrest in protestant East Belfast, said one-in-four males under the age of 16 in that area are functionally illiterate and come from families where other generations have never been employed.
With jobs in areas such as technology replacing the once reliable industrial employment offered in shipyards like Harland and Wolff, which a century ago built the Titanic, uneducated young people in East Belfast have few, if any, opportunities.
Community workers like Houston say a first meeting of the new 'Unionist Forum' on Thursday, where politicians will meet to seek to address the communities' issues, will help but is unlikely to yield the quick fix needed at grassroots level.
Instead exasperated residents, who have seen militant Irish nationalists become more active in recent years by killing three police officers and two soldiers, may simply have to wait for rioters to get bored of fighting with police, he said.
For nationalist politicians, whose communities have so far mainly stayed on the sidelines with the exception of those militant factions who attempted to kill a policeman with a car bomb last month, a Unionist-led solution will not work.
Protestant protesters have complained that the removal of the flag was a step too far in the ebbing of their dominance in the province.
Gerry Kelly, policing spokesman for Sinn Fein, the former political wing of the Irish Republican Army (IRA), says the decision to fly the flag on 17 specific days a year simply brings Belfast in line with many other town halls in Northern Ireland and the rest of the United Kingdom.
"We can sort this out collectively but there has to be a realisation that we're not just talking about one issue, we're talking about a series," Kelly, who served 15 years in prison in relation to a fatal bombing in the 1970s, told Reuters.
"We have a difficulty - it's the beginning of the year, the marching season is ahead of us. Am I worried about it? Yes, I am but I do think we have overcome bigger problems that this before and we can do it again," said Kelly, whose party shares power in the devolved government with its former Unionist foes.
Kelly was referring to the divisive summer marching season when Protestant groups hold traditional parades that are seen as provocative by Catholic nationalists and often turn violent. Police were shot at and injured last year.
The differing views among politicians shows the lingering division that makes governing its 1.8 million people a complex affair as Northern Ireland, severed from the rest of the island 90 years ago as a Protestant-majority province, sees its demographic balance tip toward Catholics.
Census data released last month showed that a majority of Belfast's population is now Roman Catholic and experts predict that Catholics could become a majority of the whole province's voters within a generation.
However for most people on the streets of Northern Ireland, who were looking forward to a year when the province plays host to the G8 summit of world leaders, there is no will to return to the bloody times that cost some 3,600 lives over three decades.
"The small numbers of people carrying on with violence and attacks on police will never win," said Adrian Warren, 62, a Protestant former government worker from south Belfast.
"Northern Ireland will never be a war zone again because the ordinary, everyday people here want peace and want their children and families to be safe. Bombs and guns are a thing of the past and they've no place anymore."