The late Spike Milligan liked to claim that when he inquired about taking out Irish citizenship at the Irish Embassy in London, he was greeted warmly by an official who assured him that his application would be welcomed because "we're short of people", writes Fintan O'Toole

Even if the story was invented for comic effect, it had a core of truth. Until the very recent past, Ireland was demonstrably short of people

At the start of the 1960s, the Republic's population was at its lowest recorded point in modern history - 2.8 million. As recently as 1991, a census showed that the population had declined slightly since the previous one in 1986. Ten years ago, more people still left Ireland than came to live here from abroad. Even now, with a little more than four million people, the Republic has about two-and-a-half million people fewer than it had in 1841. Yet somehow the enthusiasm that greeted Milligan's decision to add to our numbers has been replaced by anxiety and ambivalence.

Immigration is such a fraught subject that much of what we think we know about the subject is wrong. What was the most common nationality of immigrants into Ireland last year? Polish? Nigerian? Chinese? Actually it was Irish - a reminder we have been migrants ourselves for a very long time. Who are the best educated foreigners coming into Ireland? Germans? Italians? Dutch? Actually, it's the Filipinos and the Indians. More than 80 per cent of those coming here from the Philippines, and more than 70 per cent of the Indians, have a third-level education, compared with half of the Germans, Italians and Dutch.

What proportion of the current Irish population is non-Irish in origin: 10 per cent, 15 per cent? Actually it's just one person in 20 (5 per cent). Immigrants are responsible for the rapid rise in the population, aren't they? Actually the effect of immigration (including the return of Irish emigrants) is still smaller than the natural increase caused by the pleasant fact that we have more births than deaths.

The 2002 census found that there were about 182,000 non-nationals living here. Probably around 60,000 non-nationals have come since then, while some of those who were here on short-term work-permits have left, so the current figure is probably over 200,000. (A further 250,000 people living here were born in the UK, but the majority are from Northern Ireland or are the children of Irish migrants, and are "non-nationals" only in a technical sense.)

There are around 8,000 Germans, 7,000 French people, 3,700 Italians, 4,600 Spanish people and a smattering from each of the old EU 15 countries. In 2002, there were also between 25,000 and 30,000 people here from each of the rest of Europe, Africa, Asia and the Americas, along with around 8,000 people from Australia and New Zealand.

Most of the immigrants from beyond the old EU 15 have come here very recently on work permits, whose annual number increased from just 6,250 in 1999 to 47,000 in 2003. Five countries - Latvia, Lithuania, the Philippines, Poland and Romania, accounted for 41 per cent of all work permit holders in 2002. Just 33,000 permits were issued last year but 53,000 people also came here to work from the new EU member-states. Almost half of this latter group was from Poland with most of the rest from Lithuania, Latvia and Slovakia.

Typically, these newcomers are young people (two-thirds are aged 30 or under) working in service industries. They are also, in general, better educated than the Irish workforce. Immigrant workers are twice as likely as Irish workers to have a third-level education and half as likely to have got no further than Junior Cert or its equivalent level.

The new migrants are, however, a diverse group, with widely different points of contact with Irish society. They are to some extent isolated from each other, as much by earning power as by cultural and linguistic differences. Central and eastern European migrants doing agricultural work, Turkish men working in construction, Asians working in domestic service and Brazilians working in meat factories tend to be poorly paid, and are open to exploitation. (The Irish experience of what it's like to be a vulnerable migrant has not made us any less likely to be swaggering bullies.)

On the other hand, Filipinas working as nurses in our hospitals, Indian doctors or western Europeans working in high-tech industries are paid as well as their Irish-born counterparts. Economics defines people's relationship with Irish society even more clearly than race and nationality do.

This influx of new people undoubtedly represents a historic change, bringing a new range of languages, religions, cultures and experiences into the frame of what had been, by the standards of post-war western Europe, a remarkably homogenous society. The shifting pattern of religious affiliation is the most obvious emblem of change. The long-term decline of southern Protestantism, a seemingly inevitable process since the foundation of the State, has been reversed by immigration, with all major Protestant denominations now growing faster than the population as a whole. The number of Muslims here quadrupled between 1991 and 2002. There were fewer than 400 Orthodox Christians in the Republic in 1991, but by 2002 there were over 10,000.

It is important, however, not to exaggerate the fundamental nature of these changes. The supposed cultural and religious homogeneity of Irish society was disappearing anyway, as part of a process that had already gathered an unstoppable momentum long before significant numbers of immigrants started to arrive.

The old Catholic nationalist Irish identity was crumbling for the same underlying reason that the immigrants have come here: economic globalisation. The challenge posed by immigration - how to create an open society that integrates people with different intellectual, spiritual and cultural identities through a common set of public values - is one already posed both by the collapse of the Catholic monolith and by the Belfast Agreement.

Which makes it all the more surprising that the official response to the challenges of immigration has been so grudging and confused. While, on the one hand, all the economic analysis suggests immigration has been a crucial factor in sustaining growth, the State's attitude to it has been characterised by neglect and negativity. Ireland is still the only country in the western world where a Minister could use a racial slur in parliament and keep his job, as Conor Lenihan did when he described Turkish workers as "kebabs".

The overwhelming focus on asylum-seekers (who make up a small minority of immigrants) and fearful responses such as the citizenship referendum encourages the public to treat the foreign-born population here with suspicion. Meanwhile, serious issues such as the exploitation of vulnerable workers or the mismatch between a diverse population and an overwhelmingly Catholic education system, get scant official attention.

It is hardly surprising that many Irish people respond to these mixed messages with mixed feelings about immigration. In a recent IMS poll for the Sunday Tribune, respondents overwhelming endorsed both the proposition that it will be good for their children to grow up in a multicultural society and the proposition that the number of foreigners coming here should be restricted. Only a third of people said they would not want their child to marry a foreigner, but two-thirds admitted they had no non-national friends. While immigrants usually feel that they belong in two countries, Irish people, it seems, remain in two minds.

Nonsi Mthunzi (21) from Zimbabwe is going into her third year in Portobello College in Dublin where she is studying law

I come from a middle-class suburb of Dulawayo in Zimbabwe which is the second biggest city after the capital Harare. It's a nice, quiet town populated mostly by Endbele people like me, with a small proportion of Shona people. I came here five years ago when my father got a job in Intel. I was 16 when I left and it was a very exciting time. Employment prospects are not great where I am from and I knew there would be more opportunities here. In Dulawayo you go to school and then university and then it is a dead end. I had never even heard of Ireland before I came to live here but friends told me it was split between the North and the South. I didn't really have a clue.

My day starts at around 7.30am when I get up to get ready for work in the cafe of a supermarket in Maynooth. I am living in Lucan and studying law at Portobello College and I need to make money to pay my fees of €5,000 a year. I am on a student visa and because I lived here for three years before starting college, I pay EU fees.

The culture here socially is very different to where I came from. Young people do not go out so much at night in Zimbabwe and they don't drink much either. We used to meet up at the city hall in the centre of town to chat and then we got a bus home at around 6pm.

It was difficult when I first went to school here, I was one of just a few black people in the school. I had really short hair and looked more boyish. People would look at me as if to say "where are you from?" They would assume I didn't know how to speak English and I found their accents hard to understand. Then I met a girl who became my friend and things started to get easier.

At work the racial issue sometimes comes up. There are some customers who make it clear they don't want to be served by a black person and they wait around until a white member of staff appears. I feel terrible when that happens, it's so ignorant, but I don't say anything because there is no point.

The rules in my house are different to an Irish household. When I come home from work at around 7pm if I want to go out I have to ask my parents for their permission. Sometimes they say yes and sometimes they say no. My friends can't believe it, they have much more freedom. It's hard to explain. My parents are very strict but it is out of concern for me and my sisters and brothers. It's a respect thing. Even though I don't agree with him all the time, I still have respect for my father's views.

Another difference is that in my culture the men do not do any cooking or household chores. In the houses of my Irish friends I notice that the fathers sometimes do the cooking but that would never happen in my house! We eat dinner later than Irish people seem to eat, around 8 or 9pm. We still prepare food that we would have eaten in Zimbabwe like Sadza. It's made from maize ground up into a fine powder and added in small amounts to boiling water. It looks a bit like mashed potato. An Irish friend of mine tried it and was really surprised at how filling it was, she could only eat half her portion. We eat it with spinach or cabbage and meat. When it is my turn to cook the dinner I have to do the dishes afterwards too. In Zimbabwe where we lived everyone had a maid, it was just a normal part of life. When we arrived here it took a while to get used to doing our own ironing and washing.

After dinner if I get permission to go out I will usually go to nightclubs in town. I love dancing but I don't like the way in some clubs the men just stand and stare at the girls on the dance floor like they are pieces of meat. They only get up to dance at the end when they are looking to take someone home.

I haven't had a boyfriend yet because my father doesn't approve of dating. He wants us to finish our education before we get involved in anything like that. I think he is afraid of us getting pregnant, becoming dependent on someone else and stuck without an education. He wants us to make our way in the world ourselves. So I have to wait until I am 25 for all that and while it can be awkward explaining this to people, I am used to it now.

The main thing I like about Ireland is the open society, the fact people can express themselves so freely to their parents and be open about their lives. Zimbabwe is a much more conservative place. What I don't like is the narrow minds of some people here who look at the colour of my skin and assume things about me like I can't speak English or I won't be as competent as a white person. I've been called the N word a lot. It still happens but I get less affected by it than I used to.

My life here is much like my life in Zimbabwe. I haven't been back in five years as it is too expensive but I will probably have to return when my studies are completed because it's hard to get a job without a work permit. But if it was possible I would like to stay in Ireland forever. I've grown to really like the place.

In conversation with Róisín Ingle