By Mark Doyle
BBC News, near Mogadishu
The road in Somalia from the edge of Mogadishu to the town of Afgooye, some 30km (19 miles) to the north-west, is a seemingly unending vista of grim camps for displaced people.
They have fled the fighting in the capital between government forces and a combination of Islamist insurgents and clan opponents of the regime.
Family after family is crammed into tiny shelters made of bent twigs and scraps of cloth.
I saw evidence of a few aid agencies, local and international, giving assistance.
But the absence of that ubiquitous feature of most refugee camps - the blue plastic tarpaulins of the UN refugee agency, used for temporary shelters around the world - is perhaps symbolic of how desperately marginalised these people have become during the country's long civil war.
If you do not even have a UNHCR plastic sheet, you are poor indeed.
"The sticks and scraps of cloth I need will cost me about $9 (£4.50)," said Binta Mahamoud, a housewife and mother who until this week lived near Mogadishu's sprawling Bakara Market.
"But I don't have enough to pay."
Mrs Mahamoud fled fighting that she believed was between government troops and Islamic Courts militia.
She was speaking on the site of what would be her new home: a sandy hovel a metre away from another destitute family.
It is estimated that 200,000 people live in these pathetic conditions along the Mogadishu-Afgooye road.
What is striking about them is that most are urban, city people; they do not belong in this arid, rural environment.
But this is just a small proportion of the total who have fled Mogadishu during this country's long civil war, a war which has caused massive human suffering.
The United Nations believes the overall figure could be around 600,000 - or half of the population of the capital.
The government says the real figure is lower, but quite how they know this, given that they only control part of the south of the country, is unclear.
The UN says the total number of people in dire need of humanitarian assistance across Somalia is 1.8 million.
But playing this numbers game is in a way irrelevant.
Until the security situation is resolved, or at least stabilised, very little aid will get to these people anyway.
They may remain largely forgotten by the outside world because the outside world has only limited capacity to help.
By way of example, I travelled to the outskirts of Mogadishu in a UN armoured car (not a military vehicle, but capable of some protection) with the head of Somalia's UN humanitarian operation, Bill Paton.
His security advisers instructed us to wear bullet-proof jackets at all times.
Armed guards are needed when travelling in Somalia
We were surrounded, throughout our visit, by UN "Blueshirt" guards with AK-47 assault rifles.
These expensive, though necessary, security measures are hardly the most efficient way of operating.
They also make it difficult to make genuine contact with the people on the ground.
There are regular shooting incidents along the Afgooye road and in the immediate environs.
The strategically important route is a magnet for Islamist insurgents wanting to make military or political capital - as well as for criminals and sometimes undisciplined militias associated with the government.
"I don't know if this is the worst humanitarian situation in the world," said Mr Paton candidly. "It may well be. But it is certainly the most difficult one for the UN and other aid agencies to address because of the insecurity."
Another example is the taxes aid convoys have to pay.
After offloading at Mogadishu port, food aid lorries have to pass through numerous checkpoints where they are taxed by armed men.
A fully loaded lorry may have to pay a total of $500 a journey from Mogadishu to Afgooye. The president of the transitional federal government of Somalia, Abdullahi Yusuf, said he was determined to clear the country of "terrorists".
The displaced live in miserable conditions
"I know the terrorists' names and faces," Mr Yusuf told me in the town of Baidoa.
"They were trained in Afghanistan by the Taliban and by Osama Bin Laden... They are al-Qaeda, of course," he said.
I asked Mr Yusuf whether he might be tempted to exaggerate the al-Qaeda threat in order to encourage US support.
"That's not true," he retorted, fixing on me with his military man's gaze. "What the US and everyone else says is true. There are terrorists in Somalia."
As we spoke in the town of Baidoa, where the government sometimes sits rather than Mogadishu because of security reasons, soldiers from the Ethiopian army stood by in their barracks in case of trouble.
This is another layer of the war in Somalia.
Ethiopia intervened - with more than a nod, perhaps, from its ally the US - to protect the weak, though internationally recognised government of Mr Yusuf from attacks by the Islamist and clan-based opposition.
While the Ethiopian intervention may have saved the regime, it also provoked a wave of nationalist resentment among some Somalis.
The two neighbours have fought several wars, and their conflicts are still intertwined.
Addis Ababa did not send in its troops just to save Mr Yusuf.
It wanted to create a buffer region to stop Ethiopian - but ethnic Somali - rebels from using Somalia as a rear base from which to attack Ethiopia.
SOMALIA'S ARMED GROUPS
Somali government troops
Ethiopian government troops
Remnants of Islamic Courts regime
Somali clans - notably Darod and Habr Gidr
Freelance militia leaders and criminals
Somali breakaway regions
The conflict may be simplified as having two sides: the transitional federal government, backed by Ethiopia and the US, against remnants of the Islamic Courts regime.
But nothing is that simple in Somalia.
In the background is always the clan war.
Mr Yusuf is from the Darod clan, one of the four big clans in the country.
Many of the business leaders who backed the Islamic Courts regime overthrown by Ethiopia between late 2006 and early 2007 are from the powerful Habr Gidr, a sub-clan of the Hawiye group.
The Darod and the Habr Gidr have fought many wars, and distrust between them runs deep.
The business leaders also backed the Courts regime because it brought relative stability to Mogadishu.
Aid agency officials told me the Courts had some very efficient administrators and that it is often easier to work with them than the current government, which some described as a divided regime.
The outside world is represented in this cauldron of forces by the UN political envoy to Somalia, Ahmedou Ould Abdallah.
An experienced Mauritanian diplomat who took on the job (some might describe it rather as a poisoned chalice) last year, Abdallah is trying to reconcile the various groups.
Quite clearly, he will need all the luck he can get.