For the first time in history, there are more pensioners than children in Britain. It's a close-run thing – 11.58 million of the oldies to 11.52 million under-16s – but it's a trajectory that we had better get used to.
According to the Office for National Statistics, the numbers of over-80s have doubled in 30 years to 2.7 million. And by 2020, the number of centenarians will have quadrupled. My grandmother's grandmother died at 102 in the earlier part of the last century of what her family described as senile decay: she was ahead of her time. Most of us would prefer to perish at that age in the style of the late Queen Mother, who was borne serenely towards her end on a tide of gin and Dubonnet.
One way of looking at the new demography is to lament the relative paucity of babies. But the more common reaction is to complain about the growing number of people living longer as a burden on the taxpayer.
Yet it ought to be a matter for celebration. Fewer people died last year (571,000) than in 2001 (599,000). That's good... isn't it? We've all got a stake in longevity. We shall have the pleasure of the company of our parents, our grandparents, our uncles and aunts for decades longer than they had. I quite like to have a couple of generations between me and death: it's a blessing few had a century ago when average life expectancy for men was 40. Many more children born this year will have the chance of chatting to elderly relations about what it was like to live through the Second World War.
Pensioners may or may not be repositories of wisdom, but they form the group most likely to vote. Which makes it all the more remarkable that their political power has been so drastically underplayed. If pensioners really mobilised, it is hard to think that the basic pension could remain at the present derisory £90.70.
Remarkably few older politicians actually go on to champion the constituency they are now part of. If, as the health think tank, the King's Fund, suggests, there will be a million people suffering dementia in a generation, our spending on health will have to be radically rethought to take account of the number of old people who will need residential care – or civilised provision in their own homes.
What's more, our idea of what constitutes an elderly person is changing – and will change more in the decade ahead. Many of our conceptions about age depend merely on our experiences of the generation before last. There are very few women now alive who lived through the First World War and could not marry after it because the males of their generation had been annihilated. But the template of the maiden aunt survived for more than a half century.
It is hard to feel quite the same towards pensioners if they begin to resemble Mick Jagger, 65, or Joanna Lumley, 62. Meryl Streep will be a pensioner next year but it's not what you think when you see Mamma Mia!
The 17th-century statesman Sir William Temple remarked that the reason there were no centenarians in France was that "they lived life too well to live it long". Our pensioners ought to do both.