By Christine Jeavans
By 2025, more than a third of the UK's population will be over 55. We're living longer and staying active until much later in life. So why the pessimism about the rise of Britain's ageing population?
Stereotypes of ageing are being challenged (© Age Concern)
It's a sunny morning a couple of weeks before your 72nd birthday and you are making breakfast before you head out to work for a few hours.
With one hand you easily flip open a pack of bacon rashers and with the other you message your mother to see if she is still up for the protest rally this weekend.
You hope you will have time to get to the post-march gig with your mates afterwards and wonder about inviting your grandson too - you've only got the one but that's normal these days.
Well no time to think about that now, you grab your gym bag for your post-work tai chi class, and head out the door.
This is not pure fantasy; all the trends identified above - from age-friendly design to flexible working after 65 - are either happening now or in the pipeline.
But it is a less familiar scenario than that conjured up by countless headlines warning of a "demographic time bomb" and looming pensions crisis.
What lies behind both visions of the future, however, is the stark and simple fact that Britain as a nation is getting older, fast.
Rise of the over-60s
In a dramatic and unprecedented demographic shift the number of young people is dwindling while the older sector of the population rapidly expands.
The underlying cause is that we are living longer and having fewer children - well below the replacement rate of 2.2 per woman - but the size of the baby boomer generation, who are just starting to retire, is accelerating the trend.
By 2014, projections suggest, over-65-year-olds will overtake the under-16s.
And by 2025, the number of over-60s will have passed the under-25s for the first time.
Life expectancy at birth is increasing but an even more telling figure is the increase in life expectancy after 60.
In the UK, a man who turned 60 in 1981 could expect to live another 16 years and a woman almost 21 years.
By 2003 this had increased to 20 years for men and 23 for women; and according to official UK projections, by 2026 this will rise to almost 24 years for men and almost 27 for women.
Even this could be an underestimate. Actuaries' charts show life-expectancy projections curving to a plateau to match the notion of a biological "maximum age" beyond which the human race cannot go.
But this theory is being challenged by research which suggests life expectancy may continue to improve in a straight line as it has done in the past.
Burden or boon?
There is evidence to suggest that not only are we living longer, we are staying healthier until an older age - something health experts refer to as 'compression of morbidity', meaning that most of us will only suffer severe age-related illnesses in the last year or so of life.
You would have thought that a long and healthy old age was a cause for celebration but there is a tendency to see the older population as a "burden on society".
Economists and actuaries worry about the dependency ratio - the ratio of children and people over 65 compared with the sector of the population that is of working age.
As the ratio rises, so it becomes harder to maintain living standards for the dependent population because the relatively shrinking workforce is put under strain.
It's easy to see why it causes concern among politicians and pension fund managers - the cosy arrangement of the current working population funding the retired breaks down if there are too few workers.
Hence the talk of raising the retirement age, of "bridge careers" to tide people over in their 60s and of forcing younger workers to pay into personal pension schemes.
But work alone is not an effective indicator of older people's economic contribution to society.
Vast numbers already care, unpaid, for their grandchildren or their own elderly relatives - a factor that is difficult to calculate in the Treasury's books but which pressure group Carers UK estimates as worth £10bn a year.
And then there's the spending power of those people - many of them baby boomers - who are lucky enough to have paid off their mortgage and avoided the worst of the pension fund crashes.
Baby boomer effect
Researchers predict that the baby boomer generation will revolutionise what it means to be old because their attitudes are so different to those of their parents.
According to market research, they are likely to be demanding and imaginative consumers of both products and services, seeking out information for themselves and refusing to be defined by their age-group.
But even before the bulk of the boomers retire, lingering stereotypes of the average senior citizen as a frail and passive creature are already out of date.
The latest available figures on volunteering show that 35% of people aged 75+ regularly give up some of their free time to help others.
Participation in society in other ways, such as voting or joining pressure groups and forums, is also high among current retirees.
Then the Saga phenomenon has revealed a love of adventurous travel and the boom in 'later love' dating websites suggests a passion for a full life.
Of course, not every aspect of an ageing society will be rosy. The division between the haves and have-nots could become even more marked among the elderly.
But as the OECD's Berglind Asgeirsdottir puts it: "Speaking of the 'burden'... will only be valid if we fail to restructure society and its institutions to reflect these new realities."
So welcome to the UK's ageing future, the revolution has already begun.