We had known from the outset of our trip that we would be meeting orphans. Unavoidable in a community where the average life expectancy is 35 years and where a generation of adults is being decimated by the killer Aids. Knowing in advance does not do much to lessen the shock when you encounter the effects of this pandemic face to face, as we discovered when we met Lackson Banda and Philemon Lackson, brothers who lost both parents to the disease when they were very young.

The boys are waiting for us. The ground in front of their home has been carefully swept. Three chairs have been placed in a row facing their front entrance, one of them, judging from its precarious list to the left, for decorative purposes only. That leaves two. One for Adrian and one for me. We sit. The boys stand closely together, a fragile wall of defence. Their faces are blank. The impression is that they are enduring an ordeal which must eventually end.

Philemon, the younger brother, is barefoot, dusty but clean. He is clearly anxious, head down, self-consciously fixing his eyes on a patch of ground to his left. His T-shirt hangs loosely on his skinny frame, holes and faded cotton in equal proportions. While clearly longing for this inexplicable encounter to be over he does not shuffle or shift. He endures, waits, expects nothing, relying on his brother to take the lead as he has probably done for the last four years. Lackson on the other hand meets our eyes calmly, his head held high, and, despite being slight for his age, there is dignity in his bearing. We notice a watch on his wrist. A gift? An heirloom? Does it work? He has the aura of the survivor, wiry, defiant, self-sufficient. His shorts may be frayed, and broken, gaping, lace-less shoes may cling by sheer will power to his dusty feet, but he is the provider, the protector, the head of the family.

He is 14 years old.

Thom Kasuba, our guide for today, and World Vision's Development Facilitator for HIV/AIDS work in this area, speaks gently to the boys. They visibly relax and sit, leaning against the sun-warmed wall of their home. Lackson stretches his gangly teenage limbs in front of him. Philemon is cross-legged, his eyes still averted, head down. ‘Just put up with it,' I can feel him thinking, ‘it will be over soon.'

A young woman dressed in a checked blouse and bright skirt steps forward to talk to the boys. We recognise her from an earlier community meeting. Thom explains that Loveness is their Care Giver. She visits the boys regularly. We already know a little about the Care Givers. Originally they had been furnished with the rather unrealistic title of ‘Guardian Angels'. We had smiled on learning that World Vision provided 43 bicycles to make it possible for them to reach those they served, needy people whose homes are scattered around the community. Guardian Angels on bicycles! The concept had seemed rather sweet and endearing at the time, slightly unreal.

Now I watch Philemon disappearing eagerly through the front door of his home to emerge seconds later with a sliced open maize bag which he carefully places on the ground for his friend to sit on. There is no physical contact but I am relieved to sense a comfortable familiarity between them as they sit together.

I whisper to Thom, "They look as if they enjoy Loveness coming."

"They do."

"What does she bring them?"

"She brings them spiritual counselling."

My mind whirls. She brings them what? Spiritual counselling? Nothing else? No food? No blankets? No clothes? No toys? No money? Even I can see that their roof is falling to pieces. And it's their winter, for goodness sake, with temperatures dropping at night to near freezing. I decide I must have got it wrong as I watch the three of them talking, and resolve to question Thom further about it. I notice that Lackson has got an ugly bite on his cheek and I long to dress it for him. Embarrassed, I turn my attention to my surroundings. The ground in front of the dwelling has been meticulously swept. A scrap of corrugated iron from the disintegrating roof and a triangle of ash-covered stones mark out their cooking area. Other boulders secure what is left of the roof. There is nothing else to distract me. There is nothing else here. Reluctantly, I look back at the boys, hating my inadequacy, yearning to dispel the horrible illusion that we are merely an audience, and a potentially hostile one at that.

At last. Adrian is asking a question. "Would you like to tell us your story?"

Philemon immediately averts his eyes. It is going to be up to Lackson. He does not fail. His eyes meet ours determinedly.

"Our mother died four years ago. Our father was already dead. They died from HIV/Aids. Our grandmother came. It was not good. Now she has gone.

She has gone to live on a farm in the bush." That's it?

I quickly scramble these scraps of facts together. By ten and nine these little boys had lost both their parents. But they had a grandmother. She came.

A year later she had gone and they were alone.

"Why - why did she go?"

Lackson's confidence suddenly falters. He looks very vulnerable. His eyes look down, the fragile strand of communication between us broken.

Something is badly wrong. His voice when it comes is small.

"She wanted to go to the bush."

"Why did you not go with her?"

Another pause.

"She was troubling us."

Troubling you?

"And we wanted to go to school. So we stay in our home. We stay here."

His head is up again. His eyes again meet ours. He is back in control. The danger is over, but there is a need in Adrian and I to press him on how two boys of 11 and ten could possibly survive on their own.

"So how - I mean, who cooks for you?"

"I cook. My mother was very sick before she died. I learnt to cook then."

"What do you eat?"

"Rats. It is rats we eat." Rats? Did he say rats? Just when I thought I was on safe ground.

"We have traps." Lackson turns to his brother. There is a swift exchange of words. Philemon shoots off into the house and returns with two small traps.

He holds one of them out silently on his flat, outstretched hand. Lackson speaks with a new confidence. Here is something practical that he really knows about.

"We go out early into the bush. We can catch 20, 30 in a day. We keep some for relish with our nshima."

Adrian and I look at each other and nod. Something we know about at last. Nshima is the staple diet in this area, a thick white porridge made from maize flour and water.

"The rest of the rats we sell."

"How much do you make for each rat?" Am I really asking this? The reply is confident. Lackson obviously takes a pride in his ability as a salesman.

"Two hundred kwatcha a rat. (two pence?) We can buy our maize with this money." He smiles a rare smile. His teeth gleam. No work for orthodontists over here. Perhaps rats'n'maize is a dish we need in the West. "If we could find enough rats maybe for 5,000 kwatcha, we could buy some secondhand clothes." He shrugs, grinning at the absurdity of his dream. The equivalent of two pounds. Riches beyond avarice! Drowning in our reactions, we clutch at the branch used by generations of adults who have run out of things to say to children. School.

"You say you stayed because you wanted to go to school. What is your favourite subject?"

Philemon whispers his shyly. "Mathematics. Bemba. (the vernacular language of the area) And English."

Lackson's eyes are bright, his face suddenly animated and temporarily free from suspicion. "Science is mine. We're learning how the sun comes out and creates days equal in length - and Geography - I really like geography."

Time for one last absurd question. "And what do you want to be when you grow up?" Lackson's reply comes instantly, with Philemeon's straight on its tail.

Evidence of long night-time conversations in the cold blackness of their small damp bedroom area.

"A Pilot!"

"A Policeman!"

Oh, Lackson Banda and Philemon Lackson. Of course that's what you dream of being. Shiny hats. Smart uniforms. Polished black shoes. Not to mention the pristine shirts, clean underpants and socks and gleaming badges. Perhaps more importantly, a sense of belonging, of being someone special. A quick tour of the dark interior with the boys as our guides illustrates what we already knew. They are very, very poor. A small rickety stand displays one saucepan, one bowl, one plastic mug, a box of matches and two somewhat tatty school books. A string, suspended across the corner from two nails, sports assorted pairs of disreputable shorts and ragged shirts, completing the boys' wardrobe. No bed. No blanket. No mosquito net. No light.

Blinking as we emerge into the startling sunshine we stand in an uneasy group. The boys have switched off, their task as informants and guides over.

We shake hands. We leave. I am walking next to Thom.

"How is it that the Care Givers bring them so little?"

Thom looks surprised. "Oh, but they do. They bring comfort and friendship. They share the gospel with them."

I feel embarrassed.

"Yes, but what about material needs. Their roof has holes. They are hungry. They have no clothes. They don't even have blankets. They..."

"They are not vulnerable enough," explains Thom in his solemn way. "You have seen how well they are coping. They are very self-sufficient. Until we have many more sponsors they will not receive much more help. There are so many who are so much worse." Worse?

Just for the record we did go back. We discovered just why their grandmother was a trouble to them. We learned that bush rats are a staple for poor rural families in this part of Africa and we got a very good recipe for roast rat. We were even able to give them a few presents (including a football, insisted on by our sons). But in the end we were left with a very strong feeling that the poverty plimsoll line needs raising more than a little. Surely it is enough to have lost both parents before even reaching your teenage years. Surely no kid should be forced to go rat-catching before school in order to stay alive. Surely boys of this age should not be soaked in the rainy season through a leaking roof, and frozen on winter nights because of having no blanket. Things must change. And they will, if more and more children like these are sponsored by those of us who have no need to revert to a rodent diet.