Andrew Carnegie, the Fife-born philanthropist who made his fortune in American steel, then gave almost all of it away, was fond of claiming that "the man who dies rich, dies disgraced". It's a sentiment to which an increasing number of Britain's so-called "super-rich" are warming, as the well-heeled begin to question the wisdom of leaving behind a fortune that will go straight to the kids.

Nigella Lawson, the television cook and daughter of the former Conservative chancellor Nigel Lawson, this week added her voice to the throng by declaring she intended to leave nothing to her children.

Lawson, 48, had two children with her first husband, the late journalist John Diamond: a daughter, Cosima, now 13, and a son, Bruno, now 11. However, second husband Charles Saatchi, 64, who has a 12-year-old daughter from his first marriage, is apparently adamant that the children should inherit their money. They are reputed to share a fortune of at least £115m - Saatchi is worth around £100m while Lawson's wealth is estimated at £15m. Although she has not stated what she would rather do with her money, she has worked closely with cancer charities following the deaths of her mother, sister and first husband from the disease.

She is just one of several high-profile millionaires who have publicly declared that they will not be leaving any money - or only a nominal amount - to their offspring. The world's most famous heiress, Paris Hilton, has appar-ently so enraged her grandfather, Barron Hilton, with her party lifestyle that he recently declared he was leaving the bulk of his $2.3bn estate to charity.

History is full of wealthy individuals who have used their will to express moral disapproval of the behaviour of a family member. Prince Rainier of Monaco redrew his will to leave his daughter Princess Stephanie only 1% of his £18bn. Nancy Cunard, of the Cunard Line shipping business, was disinherited because her family disapproved of her affair with musician Henry Crowder.

However, the new wave of disinheriting offspring is not intended to punish children, but rather springs from a desire to save them from a life without motivation. "I am determined that my children should have no financial security," said Lawson, who became a household name on the back of her cookery books and subsequent television programmes. "It ruins people, not having to earn money."

Anita Roddick, the Body Shop founder and environmental campaigner who died last September, spoke of her desire to give her £51m fortune to charity - and her decision was publicly supported by her two daughters.

Nicola Horlick, the city high-flier branded "Supermum" for managing to combine raising five young children with a demanding career, made a similar declaration. Reputed to be worth £25m, she already gives away 25% of her income every year.

Barclays Bank recently carried out a survey of around 800 super-rich individuals, which revealed that one-third were now reconsidering leaving large inheritances to their children. Many are opting to include stipulations such as the completion of further education or holding down a job. Meritocracy, the idea that we should succeed or fail on our own merits, seems to be gaining popularity among the very wealthy.

Instead of leaving huge sums to family members, more millionaires are instead giving their fortunes to good causes, according to research by Philanthropy UK, a resource for donors. Having surveyed individuals with a personal wealth of at least £5m, they discovered that not only were more people choosing to give away their fortune, they were doing so during their lifetime, in a departure from traditional legacies.

These people are also increasingly hands-on in their giving. Many are also using their business acumen to ensure the money is invested efficiently, not simply signing a cheque and walking away.

"There is a large demographic shift in the UK in terms of source of wealth towards self-made, and this is one of the main factors driving change in philanthropy," says Susan Mackenzie, director of Philanthropy UK. "A lot of the markets have done really well, there is a lot more wealth generally - and the rich are getting richer and making their money earlier by selling their companies."

Mackenzie points to the fact that 15 years ago, 75% of individuals on the Sunday Times rich list had inherited their wealth; only 25% were self-made. Now that ratio has been reversed. "People who have inherited wealth, especially through several generations, tend to view it as the family's money, it's not their money to spend; they are stewards and their role is to preserve the wealth and pass it down.

"People who have made their money tend to view it as their money and they can do what they want with it. There is also a growing fear of not wanting to ruin their children with money."

According to Mackenzie, the image of a typical philanthropist is less likely to be the 70-year-old widow who leaves a legacy in her will but a 40- or 50-year-old business entrepreneur embarking on a second career in business or philanthropy.

Scotland's first billionaire, Sir Tom Hunter, is a prime example. In July 2007, he announced that he intended to give away £1bn of his £1.1bn fortune over the next decade. Hunter said that, while he wouldn't leave his children destitute, he didn't want to "burden them with great wealth".

While grand financial gestures are generally the preserve of the super-rich, in the general population there has also been a move towards pensioners enjoying the fruits of their labour. As baby- boomers reach their sixties, many are retiring while still fit and healthy. Indeed, many of them are enjoying something of a golden age, given that they are likely to be the last generation to benefit from a final-salary pension and are reaping the benefits of a long property boom.

By 2025, people over 60 will outnumber the under-25s in the UK, and already the over-55s own 80% of the country's disposable wealth. In November, Verdict Research, an advisory group, stated that the spending of those aged 65 to 74 is expected to increase by 40% in the next decade, compared with 25- to 34-year-olds, whose spending will go up only 14% over the same period.

Professor David Bell, an economist at Stirling University, points to a rise in equity-release schemes as evidence that today's pensioners are determined to get the most out of retirement. "Finance companies are seeing an opportunity so they are trying to sell these kinds of products, and the take-up of them is increasing pretty rapidly. People are more willing to do more radical things as they get older. There are more than a million pensioners who are drawing their pensions outside the UK, which means they are living in Spain or Australia or France."

While many pensioners take equity out of their house for round-the-world holidays, Professor Bell says that taking equity out to cover the costs of care has also become quite common. At the moment there are around 32,000 people in Scotland in care homes; a quarter of these are self-funding, a proportion he believes will increase.

He adds that, for baby-boomers in Scotland, watching elderly relatives having to use their own money to fund care while free care is available will have an increasingly significant effect on how people view their savings. He also states that parents in the UK will fall more in line with the American tradition of giving children financial help early in life, then leaving them to their own devices.

"In the US, parents tend to see their main duty to their children as putting them through college, rather than leaving them a load of money when they die. In a way, parents here do help out their children; in recent years, it has been not so much student fees but giving them their first deposit on a new home because it is so difficult to get in to the housing market."

While politicians continue to quibble over tax on inheritance, and middle-class parents wrestle over how best to pass on their wealth, the words of US billionaire Warren Buffett seem particularly apt: "The perfect amount of money to leave children is enough money so that they could do anything - but not so much that they could do nothing."

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