Here are just a few things I've learned during four years of research for a book on the loyal institutions (Apprentice Boys, Orange Order and Royal Black Institution).

Most important is how horrifyingly ignorant are the British and Irish governments and peoples about the majority population of Northern Ireland. Northern Ireland is part of the United Kingdom and the Republic laid claim to it. Therefore, neither government treated it as the foreign country that in many ways it is.

I have a great respect for both the Foreign and Commonwealth office and the Department of Foreign Affairs, neither of which has been able to function in Northern Ireland. In the Republic, for instance, you will find highly intelligent British diplomats in all manner of places with all manner of people, engaged in everything from set-dancing to talking to farmers about BSE. And while Irish diplomats in Britain have a distracting and heavy burden in terms of the vast number of Irish people to whose concerns they have to pay attention, they are still mostly focused on understanding the place in which they live: Irish diplomats live among the British, their children go to British schools, they shop in British shops and they know ordinary people as well as the chattering classes.

British diplomats deal with Northern Ireland purely in terms of Anglo-Irish relations. For most of the history of our state, Irish diplomats have virtually ignored the place. With the advent of John Hume came a change of direction. Hume forced successive Irish governments to put Northern Ireland high on their agenda, but they obediently adopted his perspective and did his bidding. So Northern Protestants found themselves under the theoretical protection of a government that didn't know them from Tibetans while the Republic of Ireland was jigging to the Hume tune. Since the Anglo-Irish Agreement, our diplomats have, of course, become much better informed about the North. Yet they have operated either in Dublin or in a safe enclave in Belfast and those who visit the North to talk to movers and shakers are almost wholly confined to academics and politicians.

Thanks to terrorism, the normal intercourse that should have existed between the South and the North has been savagely curtailed. How many people in the South have ever had a proper conversation with an ordinary Northern Protestant?

Having spent years at Anglo-Irish conferences and having known most of the few Ulster Protestants who attend such gatherings, it was a shock to me to realise, when I began to spend time with rural Protestants, how very little I understood. Unfortunately, people in the Republic, in their state of blissful ignorance, don't see it that way.

Here is a random sample of the cherished prejudices which I get thrown at me again and again as great truths by people who have never spent even 10 minutes with an ordinary Orangeman.

Ulster Protestants have a siege mentality

Quite true, but why shouldn't they? As one of them put it: "We'd abandon our siege mentality if they'd lift the bloody siege". They have, after all, seen relatives, friends and colleagues murdered over 30 years for the crime of being loyal to their country.

Catholics are tolerant: Protestants are bigots

As an Orangeman pointed out to me: "We're all bigots in Northern Ireland. The worst are those who don't admit it." Cardinal O Fiaich put his finger on the truth when he remarked that most of the religious bigotry in Northern Ireland was Protestant, while most of the political bigotry was Catholic. One tribe is as bad as the other.

Rubbish. We treated Protestants well: they treated Catholics appallingly

Hmmm. Between 1911 and 1926, the Protestant population in the South fell by 34 per cent, at a time when the Catholic populations in both North and South fell by just 2 per cent. We know all about loyalist pogroms and discrimination against Catholics in the North, but little about the widespread terror used against Protestants in many parts of the island and the success of an authoritarian Irish Catholic Gaelic ethos in driving them out or frightening them into silent submission.

They despise Catholics

Well, actually no. They are afraid of those Catholics who want to bomb or bounce them into a united Ireland. But where Protestants can trust their Catholic neighbours, there is true friendship. I have been in innumerable Orange homes where I was met with warmth, kindness and openness, despite their knowing I'm an atheist Catholic from Dublin. I have made some wonderful friendships.

But Orangemen are instructed to be anti-Catholic

No, to be anti-Catholicism. As we used to be enjoined to have no truck with heretics, they are enjoined by their institutions to give no countenance to the unscriptural, superstitious, and idolatrous worship of the Church of Rome, not to marry into it and so on; they are equally enjoined "always to abstain from all unkind words and actions towards its members".

Orangemen march as an expression of their triumphalist supremacy

Aside from there being supremacists on both sides, how does this tally with the Rossnowlagh parade along a deserted country road in Donegal being the all-time Orange favourite? Yes, Orangemen parade in witness to their devotion to bible and crown, but also because the music and the colour of parades are a vital part of their culture.

Catholics are under siege in places like Drumcree and the Lower Ormeau Road

Here are just a few points about the background in one of those areas: Orangemen have walked down the Garvaghy Road since 1807; it is a main arterial road; until about 30 years ago it was virtually uninhabited; when the housing estates were built, all Protestants were driven out from the Upper Garvaghy Road by republicans and replaced by Catholics driven out of other estates by loyalists; of 900 Catholic houses, only 60 can actually see the road; in 1994 there was no trouble over a seven-minute parade from Drumcree church; in 1995 Breandan Mac Cionnaith, who is anathema to Protestants because of his conviction for helping to blow up the Royal British Legion Hall in Portadown, became spokesman for the residents' group. Protestants see this and other residents' groups as part of a Sinn Fein strategy to destabilise Northern Ireland.

Well, anyway, it is wrong that they should be allowed parade where they're not wanted

What Sinn Fein is proposing is cultural apartheid at best, cultural genocide at worst. As the Rev William Bingham, the Orangeman who called for the end of the Drumcree protest after the murder of the Quinn children, put it: "If there is any hope for Northern Ireland, we have to be tolerant. That means that if Catholics can't like Orange marches they should put up with them, just as I put up with GAA cavalcades flying tricolours and playing republican songs tearing through my village."

Ruth Dudley Edwards is the author of The Faithful Tribe: An Intimate Portrait of the Loyal Institutions (HarperCollins)