From football stadiums to hospitals, daily life in Ulster remains blighted by historic hatred

Northern Ireland's sectarian conflict claimed another victim yesterday when the country's Catholic football captain was forced to declare his international playing career at an end after a death threat purporting to have come from loyalist paramilitaries. For Neil Lennon, 31, who plays his club football for Glasgow Celtic, it was time to say "Enough is enough".

And though loyalist paramilitaries insisted the threat which forced him to pull out of Wednesday night's friendly match against Cyprus was bogus, there seems little prospect of a change of heart.

He may have achieved financial success and respect as a top-class player in England and Scotland, yet still Lennon found himself unable to break free of the historic animosities that blight so many aspects of life in Northern Ireland. Indeed, before Wednesday's dramatic events he had been the victim of previous sectarian threats, and his family had been targeted by loyalists.

Yesterday he had clearly had enough, and sought to draw a line under the affair. "My parents were pretty distraught really," he said. "I've got a 10-year-old daughter who knows nothing about this and we're going to try to keep her away from it as much as we can. Obviously I can't put them through this every time, you know. So, I've thought long and hard about it and I've decided that I probably won't be going back to play for Northern Ireland."

But the death threat to Lennon is just one of many forms of prejudice which infects Northern Ireland. At its most virulent and public, it manifests itself in the assassinations which cost many hundreds of lives throughout the Troubles, when so many people were killed simply or principally because of their religion. Such killings still occasionally happen, along with the bitter street clashes which still erupt in several parts of Belfast.

But sectarianism also takes many other less lethal and less visible guises, permeating society at many levels. In one apparently innocuous form, it can be seen in the way most people automatically set out to establish the religion of a new acquaintance. This can be identified by name, address, school attended and other information, so any individual can be quickly placed into the correct religious pigeon-hole.

Co-religionists often ask each other, in a phrase which has ironic overtones in the Lennon affair: "What foot does he kick with?" This is code: the right foot denotes a Protestant, while a "left-footer" is a Catholic. The routine nature of such checks indicates the centrality of sectarianism. They are not necessarily seen as evidence of bigotry, but rather as an essential way of identifying an important characteristic.

Conversations which take place among people of one religion are much less guarded than those among the religiously mixed. This is because most regard politics and the Troubles as topics simply too explosive to be discussed freely.

In the wake of violent incidents many confine themselves to saying, "It's terrible", and avoid any deeper discussion. Seamus Heaney reflected this avoidance of dialogue when he noted the unwritten rule: "Whatever you say, say nothing." Gatherings with only Protestants, or only Catholics, present are known as "safe company". In these, politics can be discussed in detail, freed from the constraints of observing the sensitivities of "the other side".

While such mechanisms may be viewed as craven they have proved useful – particularly in workplaces where Protestant and Catholics work side by side – in helping to avoid outbreaks of divisive disputes. Workplaces are among the few places with any element of integration, or at least co-existence. But this is not always the case with threats emerging from outside.

Workers at three Belfast hospitals staged a protest this month when a group styling itself the "Catholic Reaction Force" said it would kill three members of staff who had links to the security forces if they turned up to work.

There was also widespread anger in Londonderry over the response to the killing of David Caldwell, a construction worker, by the Real IRA. The city's postal staff stopped work after a sectarian threat against a colleague.

Many other facets of life are and remain segregated, with people tending to attend different churches, live in separate districts and attend separate schools. Recent research suggests housing segregation has become more marked, and certainly the two sections of the working class in Belfast live almost entirely separately. Some, in fact, live behind peace lines to keep them apart. In such circumstances it is all too easy to come to think of the other religion as the enemy.

There are, of course, thousands who regard themselves as non-sectarian and indeed anti-sectarian, but they tend to be in a minority. There are also thousands of mixed marriages, and almost all of the people in them concentrate on making themselves invisible. Extreme loyalists in particular have a real hatred of mixed couples, often targeting them and attacking their homes. Many such couples confine themselves to a few relatively safe areas, living discreetly and taking care not to advertise their presence.

Sectarianism is sharper and more obvious on the Protestant and loyalist side, where many extreme elements regard the Catholic community as a whole as the enemy. In this mindset, Catholics, even those with absolutely no political affiliations, are viewed as communally menacing. This helps explain why most of the 1,000 victims of loyalist paramilitary groups were uninvolved Catholics, often chosen at random or simply for convenience.

Reflecting this indiscriminate approach, loyalists held in the Maze prison decorated their wing with the slogan, "Kill 'em all. Let God sort 'em out." Murals in loyalist areas of Belfast proclaim, "KAT – kill all Taigs". Loyalists have traditionally been more aggressive in trying to assert supremacy over Catholics, which helps explain why more than 90 per cent of the thousands of annual marches are Protestant. Hardline loyalist districts are likely to be festooned with flags, bunting and painted kerbstones.

In political terms, large numbers of Protestants vote for the Rev Ian Paisley, who has always trumpeted his anti-Catholicism. The main Protestant party, the Ulster Unionists, have institutionalised connections with the Orange Order, which is overtly anti-Catholic.

Few deny there is also bigotry and sectarianism on the Catholic side, though most observers agree it runs at a lower level than among loyalists. Catholics say the more extreme Protestants take the lead in sectarianism, one senior nationalist saying privately: "Prods are bigoted, Catholics are bitter." The IRA and Sinn Fein maintain strongly that republicanism is a political movement and not a sectarian one, but this tends to cut little ice with Protestants. When police were killed in the Troubles the IRA would say it was attacking the uniform. Many loyalists saw it as an attack on Protestants.

Sectarianism is most obvious in working-class areas, often in the poorest districts, but it exists within better-off areas as well. Many say the Protestant middle-class exodus from north and south Belfast in recent times is in part motivated by sectarian attitudes. Thousands of Protestants have departed for satellite towns as upwardly mobile Catholics moved into desirable districts. One Catholic lawyer said: "I overheard a Protestant say he was getting out because the place was getting like Vatican City."

Sectarianism has its black-spots. In Lennon's case, he comes from the town of Lurgan, next door to the loyalist citadel of Portadown, scene of the annual Drumcree confrontation. This is among the spots where sectarianism is rife.

The Loyalist Volunteer Force, whose name was used when the Lennon threat was delivered, has denied involvement. But the group is so unpredictable and undisciplined that it is prudent not to rely on its word. None of this is a recent phenomenon. Serious and often fatal sectarian clashes regularly broke out long before the state of Northern Ireland came into being in the 1920s. Many incidents were in areas still troubled today: the first associated fatality in Short Strand, where disturbances continued this week, happened more than 100 years ago.

The sectarian element was built into the system when the state was founded, on the basis that a Protestant majority was, in effect, given control over a Catholic minority. The state was born in violence, with more than 400 killed in two years.

Sectarian patterns have been a feature of its existence, since religion is regarded as a badge of national identity: most Protestants see themselves as British, and most Catholics regard themselves as Irish.

This underlying political difference, and the never-ending debate over whether Northern Ireland should be British or Irish, means sectarianism is ever present, an apparently ineradicable virus built into the fabric of a divided society.

* The operational capability of police in Northern Ireland is seriously over-stretched and approaching a critical point, the departing police chief, acting Chief Constable Colin Cramphorn, warned yesterday. He said the 15 months of disturbances had left the dwindling force dangerously depleted.