Managing human population growth will be one of the biggest challenges of this century. Two years ago, I remember being alarmed to learn that, somewhere, the seventh billion human being had been born.

When we are struggling to provide work and homes – even in this still rich country – for our own British young people, how are we going to provide similarly for such numbers in its poorest regions? Even more worrying is that some pundits estimate the planet’s population will not level off until 14 billion has been reached (even in the best scenario, it is said to level off at around nine to 10 billion in the 2060s). Even David Attenborough has expressed his concern in a recent interview, describing the human race as “a plague” on the planet.

Ukip’s 2nd place finish in the recent Eastleigh by-election has been attributed by many to the party’s focus on immigration. And with the expected influx of Romanian and Bulgarian workers next year certain to add pressure to our already stretched public services, the British public has a right to be concerned.

Our own island serves very well as a microcosm of what is happening beyond our shores. When the Romans arrived here 2,000 years ago, it is thought that between 1.5 and 2 million people lived here. It took the whole fifteen-hundred-year period, right up to the reign of Elizabeth I, for that number to double. Yet in just the next 500 years it grew fifteen fold. If we already have a housing problem with strains on public services such as hospitals, schools, transport, only a person in denial would dispute that the expected influx of Eastern Europeans would not further exacerbate it greatly.

Like other developed countries around the world, the UK has a demographic time bomb about to explode; many would argue that a smaller and smaller workforce supporting a larger and larger retired sector is an even more alarming problem than that posed by rising immigration. Yet if Britons’ birth rate is insufficient, they say, we must bolster it with fecund young people from abroad. This, we have to admit, is a cogent argument.

What was needed (and still is) was a national debate in which all these issues could be thoroughly aired. But we didn’t get it. What we got from the Blair government instead was a sly and silent opening of the floodgates, which resulted in a totally unfocused rush towards this country of people with minimal skills and often a hostile outlook towards us. The flood was greater than any known in our history before. It was, in fact, a scandal, perhaps even a crime. What was actually needed was a measured import of those high in skills of the sort this country could have benefited from economically. What was not needed was what amounted to an assault on the working classes by importing people who would work for next to nothing and take the jobs which otherwise would have been theirs. The crime, as I see it, is here.

Yet I believe there was also another crime in pursuing a policy which has the capability, perhaps, of changing the character of our nation forever without securing the consent of the people.

I believe in being open and accommodating to people of all races. After all, no people on the planet have had greater experience of rubbing along with people from other cultures. Ours was the most benign, dynamic and just of all the European empires. Indeed, a local Algerian shopkeeper once told me he saw his own father shot dead before him by the French during their war for independence. Better, he said, had Algeria belonged to the British Empire. “Why? I asked. “Well, they were gentlemen,” he replied.

I’m not saying we never did terrible things: consider Amritsar in the Punjab in 1919, when Ghurkhas under a rogue British brigadier shot dead 400 people at an illegal protest gathering. But at least there was a hell of a public hullabaloo, and a court of inquiry afterwards.

Yet despite such isolated incidents, none of the other former empires have been able to inspire such warmth and a feeling of togetherness. We therefore have no need to take lessons from anyone in how to treat people from other lands. Except, perhaps, from that other former colony of ours which feels the greatest warmth of all to us, but which, strangely, does not belong to the Commonwealth: the United States. There, if you want to make that country your home you have to accept all its values; citizenship comes as a complete package. You must be an American first, and a Hispanic, Japanese or Pakistani second. The U.S. does, however, have problems with its own burgeoning population. But at least it enjoys the luxury of having 32 times more space than we have.

It seems certain that whatever measures the world takes, it cannot hope to stop that seven billionth baby being joined by another three billion others before this century is halfway through. But I believe that human resilience will win through in the end. This has to be by raising living standards in the Third World. Only by spreading prosperity will you put effective brakes on population growth. Show me a First World country with an out of control birth rate (except, that is, where out of control immigration has been allowed).

The greatest service we could do for Africa is to get rid of the protectionist and cruel Common Agricultural Policy. Our chance to do that is coming soon when the Euro nations need our agreement for treaty amendments in the years ahead. Plus, we must bite the bullet where GM foods are concerned. Contrary to what Prince Charles may believe, only with vastly increased yields will we have any hope of filling all those extra hungry mouths.