Nelson Mandela will be 90 on July 18. To celebrate - and raise money for his Aids charity - he will attend a star-studded concert in his honour in London next Saturday. He promises to be as inspiring and indomitable in his nineties as ever. Life can be sweet for nonagenarians who, like him, remain in relatively good health and spirits, as the three fiercely independent people on these pages testify.

The chances of reaching a ripe old age have increased considerably: 90 has, in effect, become the new 80. But life for many people in their nineties can be grim; they are disabled by physical or mental ill-health, or have a poor quality of life because they feel isolated, undervalued and bored. Depressingly, a report for Help the Aged claims that nearly half of all pensioners have only the television for company.

As the gap between longevity and healthy life expectancy widens, more people need looking after, either at home or in residential and nursing homes, a prospect that is universally dreaded and costly.

Current estimates are that by 2050 we will need to spend four times as much as we do now on social care. A recent report for the King's Fund also highlights the practical and financial challenges posed by the predicted rise in dementia, which at present costs the country £14billion, more than heart disease, cancer and stroke combined. The report predicts that this will rise to £35billion by 2026.

So it's not surprising that the care of the elderly has finally reached the top of the public agenda. Last month Gordon Brown launched a nationwide government consultation on the funding of social care over the next 20 years, which will culminate in a Green Paper early next year.

The first step will be the introduction of personal budgets to allow people to choose what kind of care they want to spend their money on - either at home or in a home.

But a healthy old age and a good quality of life are not just about money. There surely needs to be more thought about individual needs and imagination about how it feels to be old yet wanting desperately to stay independent - at one extreme to have difficulty changing a light bulb, and at the other to relinquish control over your own life and routines.

Yet, despite the fact that this is the fastest-growing age group in the country, relatively little information is available about the health of people over 85 - “the oldest old” - according to researchers at Newcastle University's Institute for Ageing and Health.

A study of 1,000 people over the age of 85 being conducted by the Institute for Ageing and Health will, hopefully, provide useful insights into the combination of biological, social and medical factors that help to influence a healthy and happy old age.

Prilly Crowther

Prilly Crowther was 90 in April. She has lived in the same large house in West London since 1924; she now shares it with her daughter's family.

Crowther worked briefly as a commercial artist before her five children were born. She has 14 grandchildren and six great-grandchildren.

I'm constantly surprised that I've got this far and I'm lucky to have reasonable health. I have had a heart attack in the past and I just live on pills, but I don't worry about things; it's a waste of effort. I'm also terribly forgetful and I'm as deaf as a post, but I have wonderful hearing aids.

I decided to give up driving two years ago. I was shocked that they renewed my licence without another test and I realised that at any moment I might not be as bright as I thought I was.

Anyhow, now that I'm on my own I take taxis and I've got a bus pass. I use a stick because I'm a bit wobbly, but that didn't stop me protesting at the town hall recently about our local Post Office closing.

Occasionally I've been stopped by youths wanting money, but I put on a grandmotherly voice and say “For goodness sake grow up!” Fortunately I've got a large and supportive family to keep me on the rails. My daughter Lucy's family moved in upstairs while they were looking for a house 17 years ago. It's a perfect arrangement: we dash up and down borrowing butter and eggs, and they pop in to see if I'm OK.

My grandson, who is 15, drifts down in the evening if he gets fed up with everybody upstairs. We sit and watch TV or something and then he drifts off again.

It makes such a difference to know that there's someone there if you're stuck, or if you need a light bulb changing. But otherwise I'm independent. I cook my own meals and constantly have people to stay.

Most of my family live in the country and the bliss of living in London is that people come up for meetings and things, and need a bed for the night. I've just had a granddaughter living with me for three years.

My husband died seven years ago; we'd been married for 63 years. I was so thankful that he died before me because I know he couldn't have coped without me. It sounds arrogant, but I don't think he would have liked even his own family to look after him.

Over the past ten years I've lost a lot of very good friends, both men and women, and I miss them dreadfully. You think, “I must tell so and so something” and then you realise that they're not there.

I've always been interested in people. I don't waste time brooding about myself because there are so many other things to think about. But then I'm lucky. Many people of my age aren't mobile or are in constant pain, and then how can you not think about yourself?

I stlll sew and knit, though not nearly as much as I used to. And I garden like mad in a rather ineffectual way. It's extremely comforting and pleasant.

Leslie Thackaray

Leslie Thackaray, 92, has lived on his own near Bakewell in Derbyshire since his wife Maisie died ten years ago. Family photographs cover the walls of his bungalow, which overlooks a well-tended garden. None of his three children and eight grandchildren lives locally but they all visit regularly. Thackaray, a former civil servant who worked for Ordnance Survey, was a prisoner of war in Greece between 1941 and 1944.

I have a strict routine. I get up when the paper boy comes between 6.30am and 7am, take a pot of tea back to bed and read The Guardian backwards. I have breakfast between 8.30 and 9, depending on what I've got to do. Not that I've got anything to do, but you make up routines; you can even feel you're running late.

I always do my big shop on Tuesday and get the bus into town. In the Co-op they always say “Home delivery, Mr Thackaray?” I like them very much. I pay the paper bill and then go to the butcher.

Every Thursday afternoon I go to my reading group. We've nearly finished the fifth volume of Proust's In Search of Lost Time, which is literally what I do all the time now. I find it fascinating: it strikes so many notes in your own life that you go off into your thoughts.

I try to walk down the garden every day. I grow tomatoes in the greenhouse, lettuces, cabbages, runner beans, beetroot and rhubarb. I've gardened all my life, but I need help since I had a minor stroke seven years ago. And a fortnight ago my leg went, halfway through planting runner beans, and I couldn't get up. I managed to get to my feet eventually, but I find it frustrating that I can't walk so well as I used to.

I am a natural optimist. I've never been afraid of being alone and I've always been able to entertain myself. I think being a prisoner of war may have something to do with it. What keeps me going is my brain; I'm blessed with a reflective mind.

I'm more aware of death now. As you get nearer to the winning - or losing - post you're bound to become more conscious of it. I often wonder what happens to your soul. It's hard to think of Maisie doing nothing at all. I believe that she knows what's happening to me. The flowers in the sitting room were for her birthday, June 9.

I don't watch much television and usually go to bed near the end of Newsnight. I'm not religious but prayers come into your head willy-nilly. I have a little routine last thing at night: I go through all my family, starting with Maisie, in order. I often fall asleep doing that.

Ruth Kirkby

Ruth Kirkby, who is 92 next month, moved to a BUPA nursing home in Ilford, Essex, a year ago. Kirkby was a dressmaker for Harrods, then worked as an accountant for the Post Office (later BT). She was engaged twice, but never married.

I was perfectly healthy and looked after myself without any help until shortly after my ninetieth birthday, when I started to lose my balance and had a fall. Then later that year I was admitted to hospital with an infection. I was terribly ill. In fact, I wanted to die and I lost the ability to walk. So now I get around in an electric “shopper”.

I've got a lot better since I first arrived here. I wondered what I was coming to: it's such a big change after being so independent.

Naturally I miss my house. I had to sell it and left it nearly 80 years to the day that my family first moved in. I looked after my mother there until she died in 1962.

This is a nice place and the staff are friendly and kind. I suppose I will get used to it more and more. But I must say it is the worst part of my life because I've never been so ill and because at home I could do what I liked. You can here, too, within reason, but it's not the same. We have our evening meal at 5pm and I'm helped into bed by 7.30pm.

I ring my mates every evening; friends have always been very important to me. Some have died, of course, and some have ended up in homes, like me.

“Everyone here is very friendly - those who can talk, that is - and I've made some nice friends. One lady is lovely to talk to, but she thinks she goes home every night.

At first I was a bit... you know... but now I've got used to it. You see sad things; some people call out, for example. You try to think nothing of it, but you can't help it. I do get bored. I always used to knit or sew, but now my fingers won't let me and I've got cataracts. Sometimes I wipe the table mats or roll up the serviettes into their rings. I'm going to suggest putting room numbers on them because sometimes people put their dirty napkins back. They couldn't put our names on because we die, don't we?

The men here play dominoes a lot and I join in sometimes. We have bingo twice a week and singers come to entertain us.

But what I most look forward to is my niece, Susan, visiting at weekends. My cousin's family are very good, too. Susan and I have always been mates and she buys me clothes and takes me out. I like nice clothes and I still worry about my appearance, just as I did when I went to work.

Since I've been in here I've thought back ever so much. I'm lucky; some poor devils can't do that. I've had a happy life, and I suppose I'll be as happy as I can be while I'm here. What keeps me going is my sense of humour; I can always see a funny side to life.

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