Immigration: it's one of the hot-button issues of the election. There's a consensus among the political parties that rules need to be tightened. They are responding to a widespread sense among many people that the whole thing's out of control. Any more immigrants and our small island will sink under the weight of Eastern Europeans. On the other hand, business leaders say that we need immigrants to keep the wheels of commerce turning, and that financially and culturally we'd be poorer without them.

Erm: I find it rather difficult to talk about this subject.

That's because you are a well-meaning, liberal-minded sort of person, and you don't like to admit that you're worried about immigration because of the company you'd be keeping. Enoch Powell casts a very long shadow.

So it's alright to ask the questions, anyway?

Yes, though the answers might surprise you. But we need to begin by distinguishing different types of immigration. For instance, we have asylum seekers who are fleeing persecution, people coming the UK from elsewhere in the European Union, and people coming from elsewhere in the world. Some of these have jobs to go to – like employees of giant multinationals relocating to London – while others don't. They are all immigrants.

Alright, then. How many people are actually coming to the UK, and is it too many?

Those are two very different questions, but here goes. From April 2013-14, 560,000 people arrived in Britain and 317,000 left, a net difference of 243,000. Of those arriving, 81,000 were British citizens and 214,000 were from other parts of the EU, leaving 238,000 from elsewhere. Of those leaving, 131,000 were British citizens and 83,000 were from the rest of the EU. So the net gain from the EU is 131,000. However, that's still quite a lot.

It's a fair-sized town. That must put an enormous strain on the health service and the benefits system.

The answer to that, counter-intuitively, is 'not necessarily'. A 2013 study by Prof Christian Dustmann and Dr Tommaso Frattini, The Fiscal Effects of Immigration to the UK, found that far from immigrants free-riding on the benefits and health systems – a key point made by some anti-immigration campaigners – they bring in far more than they cost.

Seriously? I watched Benefits Street. What about all those Romanians who didn't work?

The point is that they were desperately looking for work, if you recall. But Dustmann and Frattini are very clear: between 2001 and 2011, recent immigrants from the European Economic Area (ie not just the EU) contributed to the fiscal system 34 per cent more than they took out, with a net contribution of about £22.1 billion. Recent immigrants from non-EEA countries contributed £2.9 billion, paying in about two per cent more than they took out. Native Brits, on the other hand, actually cost the state money, generating only 89 per cent of what they received. They say: "In other words: our analysis clearly suggests that – rather than being a drain on the UK's fiscal system – immigrants arriving since the early 2000s have made substantial net contributions to its public finances. It is a reality that contrasts starkly with the view often maintained in public debate."

You're not kidding. Why aren't we told this?

Immigration is difficult to sell, for various reasons which don't have anything to do with money – and that's not unreasonable.

And these reasons might be?

For instance, the financial benefits from immigration aren't always seen in real-life communities. So there might be schools where 95 per cent of the children don't have English as a first language. They have every right to an education, but it can't be doubted that this places an enormous strain on staff. A native Brit is understandably going to be worried and resentful, and see restricting immigration as the answer.

Are you saying it isn't?

A better answer would be to identify the pressure points like this, which immigration creates, and direct very significant resources at relieving them.

But immigrants do take jobs from British workers, don't they?

Home Secretary Theresa May last year claimed that for every 100 immigrants allowed in, 23 native Brits would be unemployed. A team of economists comprehensively rubbished her assertion, however, claiming the true figure was "virtually nil". On the other hand, immigrant entrepreneurs are believed to have created 1.1 million jobs. It is a fallacy to say that there are only so many jobs to go round; people of whatever origin are more likely to be unemployed because they live in deprived areas or lack skills.

But immigrants do hog all the council housing, don't they?

A Big Issue article in 2013 pointed out that just 1.8 per cent of social tenants had moved to the UK within the past five years; 87.8 per cent were UK-born and 10 per cent were foreigners who had lived in the UK for more than five years. So no.

Are there any other illusions left to shatter?

How about the whole sponging-off-the-state thing? Dustmann and Frattini found that recent immigrants were 45 per cent less likely to receive state benefits or tax credits than natives, partly because they were young. Even corrected for age, gender and education, recent immigrants are still 21 per cent less likely than natives to receive benefits.

You seem to be saying that there just isn't a problem.

No, I'm saying that the problems aren't necessarily what people think they are. It's not that there aren't real issues – think of the school in our earlier illustration which struggles to cope. More generally, though, one major problem is community cohesion. If a lot of people from the same culture and language group arrive somewhere, there's very little incentive even to learn English or to mix with local people. In some cases this can lead to the perpetuation of abhorrent practices like female genital mutilation or 'honour killing'. (This has more to do with longer-established communities than with continuing immigration, mind.) The trouble is that this perception of difference and exclusivity can build up a lot of resentment.

Anything else?

People who argue for a relaxed immigration policy point out, quite rightly, that it's always been said that we're a small island and we can't grow indefinitely. However, there comes a point at which we have to decide whether we really want to continue to consume land, water and other resources at an ever-increasing rate. Britain's population is growing faster than that of any other EU country; that's good for business, but not necessarily good for the environment. Immigration control is part of that argument. Another serious issue is why people are coming to this country at all; it's obviously not for the weather. The answer is that for people in many parts of the world, life back home is just too hard: their countries are poor, war-torn and misgoverned. Out of a Christian commitment to peace and justice, that should really concern us.

So, to sum up?

The economic arguments against immigration don't hold water, but people really worry – rightly – about its effect on our society, because its rewards are badly distributed and the case for it isn't made. When people get worried and resentful they can start using language and holding opinions that are uncomfortably racist. But accusing people of being racists and not doing anything about their genuine concerns leaves the door wide open to people who really are racists. Christians need to do more than say, "We should all be nice to each other." We should also be very wary of politicians who use tough-sounding rhetoric about immigrants which imply an 'us and them' scenario: it's just us.