Image caption How would you cope with becoming a multimillionaire overnight?

While many rich people are driven to become ever richer, others are discovering the joys of philanthropy and giving their wealth away.

When Anne became a multimillionaire after her company floated in 2001, she was petrified - fearing her fortune would drive away the man she loved and lead her friends to desert her.

"I paced back and forth in my little living room for about four hours, with my stomach knotted with fear, because there was one person in particular I was scared of losing," she said. "What would happen when I told him?"

Ten years on, very few people know the extent of Anne's wealth - and Anne is not her real name. She spoke to Radio 4 about the dramatic change in her life, but only on the basis that she could be anonymous.

Anne's story highlights the flipside of the dream so many have of suddenly becoming fantastically wealthy.

How do you deal with the imbalances it creates in friendships and relationships? How do you feel about yourself having so much when others around you have so little? And what do you do with all the money? What do you feel comfortable about doing with it?

I think that sense of entitlement that you sometimes see in groups of wealthy people is in a way a defence against the guilt Anne, Self-made millionaire

Selfishness and greed

To Anne's relief, the man she loved did not desert her and they are now married.

"We both are incredibly grateful that we got to know each other before the money arrived," she said, but many of her friends are still in the dark.

It wasn't just the fear of losing people that worried Anne. Feeling she didn't deserve the money was "a big part" of why she felt the way she did. She also recalled that as a child she had believed that rich people were not nice people.

There was also the worry of losing touch with the real world. "There are always some people who have got more money than you so you start thinking I am not that rich really. I have only got £1m whereas he's got £10m.

Find out more Lucy Kellaway interviews Anne in One to One on Radio 4 at 0930 GMT on Tuesday 6 December 2011

A new Radio 4 series How New is the New Philanthropy starts on Radio 4 at 2000 GMT on Monday 12 December

Listen online afterwards at the above links

"You start to get a sense of entitlement. I think that sense of entitlement that you sometimes see in groups of wealthy people is in a way a defence against the guilt that 'I didn't really deserve it.'

"That sense of entitlement comes out very much as selfishness and greed. It is born out of this isolation, in a sense fear, because once you start associating with other people who have a similar level of wealth to yourself it makes life easier but you start to drift away in a little bubble."

New philanthropists

Anne is now more comfortable about having money after joining a small group of wealthy people who devote their time to philanthropy - the Network for Social Change.

She found it "totally empowering in helping me work out how to use money for good and to make a difference rather than be used by it".

Still living modestly in a terraced house, she divides her money into two pots - one for the family and the other for charitable causes.

Money to me that is not working has a sort of obscenity about it Dame Stephanie Shirley

Anne is not alone. She is an example of what some are calling the new philanthropists.

"I think people started talking about new philanthropy in the last 10 years or so and it followed a wave of money being made in the City in the UK," said Martin Brookes, the former chief executive of New Philanthropy Capital.

"It also followed some very high-profile acts of philanthropy like the creation of the Bill Gates Foundation."

New philanthropists often have a business-like focus and want to get involved in how their money is used, rather than simply donate it straight to charity, he said.

Rich list

The philanthropist and entrepreneur Dame Stephanie Shirley used to appear in the Sunday Times Rich List, but not any more.

"I was worth £150m, but I have given away enough, together with the dot.com collapse, to take me out of the rich list.

"I am terribly proud of that, because money to me that is not working has a sort of obscenity about it."

Part of her need to give comes from her background. In 1939 she arrived in Britain as a child refugee from Germany. She was adopted and feels she had many things given to her. Now she is giving back.

Some famous philanthropists Dr Johnson's definition of philanthropy is 'love of mankind and good nature'.

John Howard, the 18th century penal reformer was the first person to be called a philanthropist.

In 1865 William Booth, a Methodist preacher founded the Salvation Army using family money.

Thomas John Barnardo founded the homes for destitute children in 1867.

More recently Warren Buffett, the CEO of Berkshire Hathaway has given multi-millions to health, education and humanitarian causes.

Bill and Melinda Gates have focused their giving on global health, education and development.

She concentrates on two areas for giving - information technology, which was her professional discipline, and autism, which was her late son's disorder.

"There is almost always an autobiographical element in people's giving," said Beth Breeze, a researcher at the Centre for Philanthropy and Charitable Giving at the University of Kent.

"Essentially people give to the causes they relate to so it is not needs-driven - it is passion-driven or taste-driven.

"Philanthropy is really about people using their own money freely. That is the crucial thing."

"They are giving it voluntarily rather than have it taken through tax and giving it to something that they really get excited about and care about."

Anne, like many philanthropists, enjoys getting a warm glow from giving.

"For me what is really important having reflected on this is the community, friends, feeling that one has a sense of purpose and is doing something worthwhile.

"So the point of money is to maximise my happiness."

Lucy Kellaway interviews Anne in One to One on Radio 4 at 0930 GMT on Tuesday 6 December 2011. A new Radio 4 series How New is the New Philanthropy starts on Radio 4 at 2000 GMT on Monday 12 December. Listen online afterwards at the above links.