I returned home to Scotland yesterday from South Sudan.

Back to a land of plenty and peace - independence referendum antagonisms aside, perhaps - from a land with nothing but war, suffering and hunger. South Sudan does have oil, of course, but that has been a curse, not a blessing, that has contributed to tearing apart the youngest country in the world.

A few weeks ago in this column I described how a crisis has to meet specific criteria before aid organisations can use the dreaded F-word and declare existing mass hunger an officially designated famine. South Sudan sits on the brink of matching that criteria and I have seen for myself what this means.

Let's for a moment forget the five-point Integrated Food Security Phase Classification (IPC), the internationally recognised scale used for classifying the severity and magnitude of food insecurity, or famine. Let me instead mention a few of the South Sudanese people I met and what they face.

Among them was seven-year-old Abuk Yum, convulsing from suspected cerebral malaria in a ramshackle clinic as his mother sat helpless and afraid by his side. Another young mother, Nyaker Gatlek, told me of the horrors she confronted crowded into a camp for displaced people around the war-torn town of Bentiu.

Nyaker described how daily she ran the gauntlet of marauding soldiers who rape women leaving the comparative sanctuary of Bentiu's United Nations compound in search of the firewood vital for cooking the meagre food available. Cooking itself is near impossible, though, in a camp where rainy season floods have left water levels in places thigh deep.

Faced with the battles that grip the area outside the camp wire, people have to eat and sleep in what is effectively one giant open air prison filled with sewage-contaminated floodwater.

Here whole families sleep crammed on rope beds raised up on anything they can find that helps keep them inches above the filthy floods full of human faeces. So impossible is it to lie down that some of the 45,000 people in Bentiu have slept propped upright.

Bentiu may not be the biggest. But one senior aid worker, describing this living hell, said: "It is probably the worst camp for refugees or displaced people anywhere in the world."

What must be remembered is people stay here because it is the only refuge they have from the widespread armed violence that surrounds them. To go beyond the wire is to run the risk of rape or death from bullets and shells.

Since stepping off the plane at Glasgow Airport on my return to Scotland, it is hard to erase the images of what those South Sudanese I met are having to endure.

Here in Scotland, we are understandably preoccupied with our own political future and the challenges independence, should it happen, would bring with it.

If Scotland chooses to leave the Union, I for one hope any future foreign policy will place emphasis on the humanitarian commitment Scots are renowned for. The vulnerable people of South Sudan and many others across the globe deserve at least that.