BBC News Health Reporter
As the plane flew over the refugee camps of Darfur, in the Sudan, Morven Murchison Lochrie was amazed by their size.
A woman and child at the hospital in Darfur, pictures ICRC
Mile after mile of blue plastic sheeting form temporary shelter for over a million displaced people.
Looking at the camps, she began to realise just how great her challenge would be - co-ordinating the Red Cross health operations in the area.
For four months, working 12-hour days, the former military nurse helped with the relief effort.
Dividing her time between the camps and the capital Khartoum where she did her administrative work, Morven was able to work out what facilities were needed where.
She said relief efforts were helping get aid through to the starving people, but warned that people are just existing.
"People are living on the edge. If the money was to stop we could go into a catastrophe.
"If people forget about Darfur there will be trouble.
"In most of the big camps it is fairly well controlled and they are relatively well laid out."
There is no doubt that the aid effort is making a positive impact.
But Morven said it would not take much to tip it over the edge.
If food supplies stopped, or there was an outbreak of an infectious disease such as measles it could spell disaster.
As an experienced aid worker she had steeled herself to expect distressing scenes. But the sheer scale of the tragedy unfolding in Darfur took her breath away.
"When you are flying over the camps you think 'so many people'. Just the size of it takes you back.
"And the fact is that people have walked so far just to get help in the camps. It is the worst population movement that I have seen.
"The overwhelming image of the situation is that it is bad, even compared to other places in Africa. It is a massive displacement of about 1.5 million people and it is an increasing burden on a poor country.
"They have always been poor, and had poor health facilities. But now the potential for problems is much greater.
"They have problems with malaria, diarrhoea, measles, violence injuries and obstetric problems. Darfur has a horrendous infant mortality death rate and a high maternal death rate."
She said that as well as suffering malnutrition and common health ailments, there were also outbreaks of measles and polio, which could spread rapidly in the close confines of the camps.
The area had been declared polio free, but there have recently been 29 reported cases.
However, Morven said she was struck by how the people remained cheerful.
"When you are in the camps, you are stuck by how resilient people are and how cheerful.
"In a morning you get about 200 people waiting to go into the clinic and they are just waiting patiently.
"It is amazing when you think how annoyed you can get just waiting in a queue in the supermarket."
Morven said she was, to an extent, removed from the relentless emotional stress affecting colleagues working permanently in the field.
Patients at a hospital in Darfur. Pictures the ICRC
But said she was still deeply affected.
"You see people dying just because they have had diarrhoea and that is the bit that gets me.
"You know that if someone had been able to see them on day one they could have lived. You just feel so powerless.
"You see the most advanced cases in the hospitals, cases where the staff know they can not help.
"Sometimes they have cerebral malaria and they are at a very advanced stage and you know that it has taken them four or five days just to get help.
"I always feel really sad when I see old people. Children always have a bit of hope, but for the old people this is the end of their lives."
Hardship was everywhere, but Morven said it was the plight - and courage - of individuals that really hit home.
"I saw this one child who had needed major surgery after TB. He was emaciated and then a couple of months later I saw the same boy who was now a fat healthy little boy. I had thought he would not survive."
The Red Cross supports two hospitals in the region, one in the north and one in the west, and five primary care centres.
Morven said that the Red Cross always tried to work with existing facilities in the region so that when they pulled out of the area the structure remained.
They also work in the rebel controlled areas and recently vaccinated against measles there.
Clare McNeil, a spokeswoman for the Red Cross, said that the sheer size of the country and its disparate population was making the charity's work particularly difficult.
She said that, as well as coping with the current crisis, aid workers were also having to battle poor health facilities in the rural areas.
"Half of Darfur's health services are concentrated in urban areas despite the fact that 80% of people live in rural areas.
"Years of under funding of health facilities and a lack of medical personnel willing to work in remote conflict-affected areas, mean that villagers are often forced to cross dangerous front lines to receive treatment at distant health facilities.
"The International Committee of the Red Cross (ICRC) is now focusing its efforts on these rural communities because of the high levels of malnutrition among the population and the severe food crisis they are facing.
"Many people will be entirely reliant on humanitarian aid in 2005. By providing assistance in these areas it is also hoped that further migration to already over crowded camps will be prevented. "