The central point is that as we pursue high rates of population growth, the issue always left out is our common environment, our common heritage required for our continued existence. Until that is factored in on an equal footing with economic arguments and social arguments than we will continue to have a very facile and useless debate on immigration.

What do we know about individuals and their sense of population growth? Women in the developed world at least have control over their bodies to the point where now the average number of children per woman is only 1.6.

United Nations figures released in March for the total population rates for the planet reveal that our population will peak at around 2050 at just over 9.1 billion human beings. That's a very serious issue for us people who live on this small planet of ours. The 6.8 billion of us who are on the planet at the moment are using far more of the Earth's resources than our planet can possibly sustain into the future.

As we seek to limit our growth in population, the focus is on the poorest countries in the world. Women there have an average of about five children each. If we're to reach that level of just over 9 billion people in the world 40 years from now, that rate will need to drop to 2.5 children each.

But if we are requiring so much of the poorest countries in the world, what right do we have to grow our population at one of the fastest rates of any of the developed countries on the planet?