Jenny Winter has a beautiful office in the tranquil setting of Barretstown Castle, in Co Kildare. Outside, a six-foot clown struts around the garden.

A group of youngsters are the stars of a movie being filmed in this magnificent setting. Others are on their knees in the arts and craft room painting on a giant canvas. They are among a group of 100 seriously ill children who have come to the castle for some fun.

Barretstown's 44-year-old chief executive explains that they are mostly from Mediterranean countries and have been joined by about 10 other children from Jordan and Iraq. For the next 10 days the staff and volunteers will encourage them to take part in medically approved activities, based on having fun, to aid their recovery from cancer and other serious illnesses.Those who participate are referred by a consultant pediatrician.

Winter oversees the programmes, which also cater for families, and spearheads the never-ending fundraising needed to sustain the camp founded 10 years ago by actor Paul Newman.

Barretstown is part of the association of Hole in the Wall camps Newman established to allow sick children to "kick back and raise a little hell" and to regain self-confidence and self-esteem. When he arrives at Barretstown for its birthday bash Winter says Newman will just want to join in the children's fun rather than bask in the limelight.

"He is the nicest person. He is great fun. He just loves playing with the children."

Newman's association gives the camp a high profile that has attracted support from many of Ireland's wealthiest people. Today its governors include Sir Anthony O'Reilly, his wife Chryss and his son Gavin as well as Dr Michael Smurfit and Mr Peter Sutherland. Its directors include AIB chairman Mr Dermot Gleeson and solicitor Mr James Osborne. This week, AIB announced that Winter's would join the bank's board of directors.

Winter says these people immediately turned Barretstown into a "trendy" cause when it first started. "That halo effect lasted four years. Since then we have been beavering away. Having high profile people associated with the camp is a help and a hindrance. Sometimes people assume they bankroll us," she says.

It needs to raise €4 million a year to meet the cost of travel to and from Barretstown, equipment for the activities, accommodation, food and medicines which are all provided for free to the children. "We get a small bit of government funding, a small proportion from Paul Newman and money from our corporate sponsors. Somebody is always doing a sponsored activity to raise money for us. Every year it's a fresh challenge how to raise that money."

Winter first became acquainted with Barretstown through the pharmaceutical company GlaxoSmithKline where she worked for 20 years and which is one of the camp's biggest corporate donors. During a stint as general manager of its Irish operations Winter handed over the cheques and also participated in the camps as a volunteer. "When I first came here I thought 'wow, this place is amazing'. There is something about what it does for kids. It was only then that I started to realise the power of what it was doing. That experience stayed with me," she says.

The next phase of her career with GlaxoSmithKline would take the West Londoner back to the UK, although she continued to live in Ireland. "I went back to work in a building where I had been 10 years earlier and I remember one person greeting me and asking 'where is your office now'? I began to ask myself was I going to stay doing this for another 20 years?

"I decided that there was no point in going to another company. I had a fear of getting to retirement age and regretting that I never took time out to try other things." She toyed with a leave of absence to sail around the world and when she mentioned her unrest to her former boss, he directed her towards Barretstown. Its chief executive was stepping down and there was a vacancy. When she was asked if she would be interested, she said "absolutely".

"In my previous job I was extremely busy but I felt like a cog in a big wheel. While I was making big decisions it was always in the context of other people's input and procedures. The big difference here is that my decisions have a smaller financial impact but the human impact and the number of people involved is worlds apart," she says.

GlaxoSmithKline has pledged €1.4 million over three years to Barretstown. Another pharmaceutical giant, Wyeth, has renewed its five-year partnership with the camp for a further five years at $100,000 a year. Xtravision raised more than €66,000 last year and brings its 300 staff to Barretstown for annual sales conferences. Afterwards, they help out with whatever needs to be done there.

Winters is keen to correct some misconceptions about Barretstown. The most common one is that the children who attend its camps are terminally ill. "Most children who come here lead a full life. Some don't and that's hard but the experience should make their life a bit better."

In 10 years Barretstown has hosted 10,000 sick children - over half were Irish.

"It is very hard to capture what the benefit is. We need to carry on communicating and getting people to understand what we do. Now that we have reached our tenth birthday we want to remind people about what has been achieved."