Thanks for down learning the In Our Time podcast. For more details about In Our Time and for our terms of use, please go to BBC.co.uk.

I hope you enjoy the programme.

Hello, today I'm joined by Britain's first professor of biological gerontology, Tom Kirkwood,

from Manchester University and Alan Walker,

professor of social policy at the University of Sheffield, to discuss and explore one of the great

revolutions of our century, that of old age.

In 1900, 1% of the world's population was over 65 in the 1990s, nearly% are by the year 2020 nearly one-fifth of the

world's population will be over 65 and the percentage will be higher in Europe.

We're now living longer than at any time in our history.

How much do economic factors rather than biological factors determine what aging really means

and our attitude to it and what are the ethical, economic and biological implications of living longer.

Professor Alan Walker is a leading social gerontologist, together with his academic work in numerous

publications, he's directly involved in influencing social policy, his advisor to the UN's programme on

ageing and he's chaired the European Commission's Observatory on Aging and Older People.

Professor Tom Kirkwood is an expert on the science of aging, as well as being Britain's first professor

of biological gerontology at the University of Manchester, he's president of the British Society of

a Research into Aging. Today he publishes time of our lives, a book which overturns the notion that aging is

either necessary or inevitable. In it he says quote today's older people are the

Vanguard of an extraordinary revolution in longevity that is radically changing the structure

of society and altering our perceptions of life and death.

The price for this success, and make no mistake it is a success, is that we now face the challenge of aging.

Well first of all let's establish why this aging has occurred.

...