Over afternoon tea and biscuits, Baroness Sally Greengross OBE is preaching revolution. "Nothing like this has ever happened before," she says. "We have to make people realise what is going on and take action."
The Baroness, slight and polite, most definitely is not in the mould of Che Guevara or Leon Trotsky. Then again, the upheaval to which she refers is not of the political variety. Greengross is at the vanguard of the demographic revolution that is turning Britain's landscape a new shade of grey.
There are now more over-60s than under-16s. Not only are we living longer, we're also healthier and more active in later life. Grandad is now a trainer-wearing child of the sixties whose Christmas list is more likely to feature a Led Zeppelin CD than pipe or slippers.
For the voluntary sector, the implications of a rapidly ageing population are immense and raise issues as diverse as the right to die to equal opportunities in the workplace. According to Greengross, how the demographic timebomb is handled will result in either "a triumph of the new century or an unmitigated disaster".
An ultra busy 67 year old, Greengross is more than just another example of the vibrant "new old". For the past 15 years, she has been at the forefront of maturity politics, firstly as director-general of Age Concern for 13 years and now as chair of the Experience Corps and executive chair of the International Longevity Centre-UK (ILC). In the House of Lords, she chairs the all-party group on corporate social responsibility and is a member of the all-party group on the voluntary sector. Being independent, "mine is a free voice so I don't have to tow the party line, I can stand up for things I really believe in".
The Experience Corps and ILC are both relatively new additions to the voluntary sector. The Experience Corps was set up last year with £19.9 million of government money with the goal of attracting 250,000 over-50s into volunteering by March 2004. A Home Office survey had discovered the number of volunteers drops off after the age of 49 and the skills of an entire generation or two, many of whom were retired or redundant, were being lost.
The corps is a physical manifestation of Greengross's vision of a society that utilises the skills of its older people and she talks with unbridled enthusiasm about the latest initiatives, such as an allotment project in the North-East that sells surplus produce to the needy.
Volunteers are put in touch with charities and community groups in their area on existing or new projects and Greengross estimates 100,000 people will have signed up by the start of next year. The corps employs around 100 full-time workers, many as local animators whose job it is to match recruits with volunteering opportunities. They face uncertain futures once the money runs out but Greengross says: "We are currently working on plans to extend funding beyond 2004."
In contrast to the gritty, local feel of the Experience Corps, ILC is a much more hifalutin idea. It aims, on a global level, to "explore and address the longevity revolution and its impact on the life-course". Described as a think-tank, it sponsors research and conferences that tackle the demographic revolution, including a study on how cities are responding to population change.
Originating in the US, the ILC is barely a year old in the UK. While Greengross is equally passionate about its value, fewer facts and figures trip off her tongue than when discussing the Experience Corps. Staff numbers are "small"; so too are donations. "We have only just completed our first year. It is very early stages," says Greengross.
But are organisations like the Experience Corps and ILC filling a void that existing maturity charities should be plugging? "You are making the mistake of thinking the Experience Corps and ILC exist only to serve older people," says Greengross. "Everyone is affected by demographic changes. The Experience Corps is involved in projects that affect all sectors of the community. It is vital we get the message across that population change affects everyone."
But how do you make teenagers, for whom anyone over 30 is ancient, care about the elderly, whether they're 70- plus or the "new old" over-50s?
The furore over the phasing out of older TV presenters in favour of a more facially unblemished generation highlights our youth obsession. Greengross, herself defiantly blonde, says: "I think we're all seduced by the idea of looking as young as we can. We don't like the idea of growing old." But she points out the media is swimming against the tide: the grey pound and the grey vote have never been stronger. "Cars are being manufactured with bigger doors so older people can get in and out more easily," she says. "Housing is no longer about meeting the needs of a two-parent family with two children. Families aren't like that any more and they will be even less like that as the population changes in the future."
Greengross' obsession with the wider social aspects of ageing is a natural progression from her time at Age Concern. She maintains close links with her former employer and remains vice-president. Having built up Age Concern Enterprises into a multi-million pound business she welcomes government proposals to relax charity trading laws and dismisses criticism by Liberal Democrat leader Charles Kennedy that such a move would "blur the lines between charitable and commercial activity". She says: "I don't mind a little blurring of the lines if it means more money. I'm more interested in outcomes than processes."