TOKYO-LONDON -- Thanks to the miracles of modern technology, I'm writing this 31,000 feet above ground level, somewhere over Siberia, on the plane back from Tokyo in that limbo time zone where it seems to be neither day nor night.

And I'm pondering the meaning of Japan's population statistics, which make chilling reading for the newly-elected government after last Sunday's earthquake election.

Imagine a country that knows it is shrinking. A country that knows it is ageing more rapidly than any other major industrialised nation on earth. Which has the highest proportion in the world of people over the age of 65, and the lowest ratio of under 15s. That country is Japan.

As I reported on Wednesday, on current trends, the population of Japan will have halved by the end of the century.

It is, literally, a country that is slowly dying.

According to one United Nations estimate, it'll need to import 17 million foreign workers over the next 40 years, just to keep its economy afloat and provide enough carers to look after the elderly. (By 2050, there will be more than a million Japanese over the age of 100.)

I'm no social psychologist, so I wouldn't dare to come up with an explanation for why Japanese couples aren't having enough babies. But one theory is that Japanese women are increasingly reluctant to marry, because they think Japanese men have shown themselves unable to adapt to the needs of a new, more flexible society - and have retreated into a fantasy world of comics, video games and animated pornography where they feel less threatened.

The Japanese internet search engine Goo Japan reckons 70 per cent of Japanese men are still unmarried when they reach their 30th birthday. (Mind you, marriage rates in Italy, Norway, France and Ireland are even lower.)

So I found myself thinking at one point of the film "Children of Men", about what would happen in a world where all women are infertile and the human race is dying out. Not that Japan is descending into anarchy - quite the opposite, in fact. It is still the most orderly place I know, where no one is impatient at traffic lights, and even the hungry and homeless wait in long neat lines for their food hand-outs.

On the one hand, it is the nation of Toyota, Hitachi, Panasonic and Mitsubishi, global leaders and still very much a force to be reckoned with. On the other, it is the nation of manga comics and young women who dress up as French maids to pander to the fantasies of lonely men.

In the current economic climate, the newly-elected government will have no shortage of competing priorities. But it's already committed to increasing the children's allowance to £170 per child per month, in the hope that a cash incentive will encourage more Japanese couples to have more babies.

After all, what could be more important for the country's future?

