Mal Fletcher comments

And then there are pressures on jobs. In Europe, most immigrants are of working age. Some people are concerned that as the EU moves further eastwards, new waves of migration will threaten jobs in the West. Of course, immigrants of working age may be less likely to consume services like health care and education - and they can pay more in taxes.

In the post-9/11 climate, the fear of terrorism is an obvious challenge too. Governments are worried not just about importing terrorists, but about giving shelter to people who will assist or facilitate terrorist actions. Sometimes, in responding to these threats, governments can go too far the other way, closing the door to genuine humanitarian concerns, like resettling refugees and asylum-seekers.

Perhaps the greatest challenge in the management of modern immigration, though, is what some have called 'cultural conquest'.

Some commentators already believe that Europe may one day be swallowed up into a new entity they call Eurabia, with a predominantly Muslim population - perhaps before the turn of this century.

I think that may be a little extreme. It's true that right now Muslim birth rates in Europe are way ahead of the rest of the community. But within a few generations the birth rates of immigrant populations tend to come back into line with the mainstream.

And, while Muslims make up a higher proportion of the youth community than they do society at large, this isn't necessarily a social problem unless it is combined with poverty, unemployment and long-term alienation - as we saw in France during the riots of 2005.

But there is a valid question here. How do we keep our doors open without compromising the values on which our civilisation was built?

The cause of immigration isn't helped by the stories we read in our newspapers, about young people who appeared to be well assimilated only to commit crimes in the name of radical Islamism. That's exactly what happened with the London Underground bombings and the murder of a Dutch Filmmaker in 2004.

However, before we cry too loudly that other cultures are going to swallow us whole, we should ask ourselves one very important question. What exactly are we trying to assimilate people into? If our culture is weak enough to be overrun, why is that?

If the West is open to cultural conquest, it may not be so much because of the strength of other cultures, but the weakness of our own spiritual convictions.

Secularism offers no balwark against the 'cultural conquest' which some seem to fear.

In my view, Europe without the Christian concept of God may look attractive in the short term, but without a commitment to faith and family, and a focus on pleasure and personal fulfilment, it will have trouble making room for selfless duty and community cohesion - the things that make a society strong.

Thankfully, we don't need to write off Christianity and its cultural influence just yet! There are hundreds of forward-thinking, positive and proactive churches springing up in Europe today.

Church membership in Europe has definitely declined over the past 25 years or so but this decline in institutional membership - where people go to church now and then because it's part of their culture - may be giving way to more vibrant, grass-roots expressions of Christian faith and fellowship.

The debate regarding levels of immigration will rage on, but we take care not to step into xenophobia or stereotypes, at the same time recognizing that the strength of our own traditional culture and values is based in Christian principles.

In fact, they're a large part of what has made our civilization attractive to newcomers.