One month into President Robert Mugabe's brutal campaign of demolition and displacement, which has cost at least 400,000 people their homes and livelihoods, the scale of the humanitarian disaster is emerging. The victims of this forced expulsion - which has been compared to the devastating policies of Pol Pot in Cambodia - are arriving in the already famine-stricken countryside, where, jobless and homeless, they are waiting to die. Unofficial estimates obtained by The Independent suggest the death rate is already outstripping the birth rate nationwide by 4,000 a week.

The UN has responded by dispatching a special envoy, Anna Tibaijuka, who arrived in Zimbabwe last night, to assess the position. The Tanzanian official, head of the UN habitat programme, is expected to be taken on a carefully organised visit to urban areas where evidence of the pogrom has been hastily cleared. The St Anne's Catholic mission in Brunapeg will not be on her government-controlled tour. The remote outpost, south of Bulawayo, has found itself on the front line of this new battle for survival. A grinding two-hour drive along a rocky dirt track from the main road linking Bulawayo to the Plum Tree border crossing into Botswana, the mission provides the only prospect of medical help for a hundred miles in all directions.

Each day scores of starving and sick people come trekking out of the bush in search of a doctor. Many barefoot and exhausted after walking for up to 12 hours through the night, they form a queue outside the spartan concrete compound and wait.

Pedro Porrino, a Spanish physician who has been working at the mission for three years, says that what is unfolding is an unprecedented crisis. "For the first time I am seeing people who are literally starving to death," he says. "There are people coming to the mission asking to be admitted just so they can eat... Out in the bush families are living on one meal a day."

HIV infection rates in Zimbabwe have soared to the highest in the world and in combination with the growing impact of malnourishment - in a country where the United Nations World Food Programme estimates that four million people need immediate food aid - the effects are devastating.

"Ninety per cent of the people I see are HIV-infected," says Dr Porrino. "Most of the time I wouldn't even need to perform the test; I can see as soon as I look at them that they have HIV. I am seeing men of 25 and 35 weighing 45 kilograms and it's because they have Aids but it's also because they don't eat at all."

With proper nutrition and medical care, HIV sufferers in the West typically take up to 10 years to develop full-blown Aids. For the starving Zimbabweans, their immune systems already weakened by malnutrition, the transition is now a matter of months.

"The speed of the transition is related to malnutrition. Every day I am seeing the evidence of malnutrition among non-HIV patients so you can imagine what is happening to HIV-infected people," Dr Porrino says.

According to one senior consultant surgeon in Bulawayo, who preferred not to be named, the scale of the Aids epidemic has so far masked the extent of the famine. "Put simply, people are dying of Aids before they can starve to death," he said.

Brunapeg is typical of the drought-ravaged areas into which Mr Mugabe is driving the urban poor. The hospital and school rise out of the low scrub, the only buildings of any kind for miles around. Rusting petrol pumps stand idle at the filling station, there hasn't been a fuel delivery in Brunapeg for years.

"Now that people are being forced to come out here what's here for them? Nothing," says the Spanish doctor.

"There are so many people here who have never been into town. The only thing they know is to eat and to survive and now they can't even do that."

With the rural famine gaining lethal momentum, the gap between the political rhetoric of Mr Mugabe, in the capital, Harare, and the situation on the ground has reached surreal proportions. Mr Mugabe, in power since 1980, has pronounced himself pleased with the results of the campaign that he has titled Murambatsvina, which means "drive out the rubbish" in Shona.

The wholesale destruction of shantytowns, squatter camps and street markets from the outskirts of Harare to the majestic Victoria Falls, is hailed by the ruling Zanu-PF as an overdue clampdown on illegal settlements and the criminal element on the fringe of society. The Education Minister, Aeneas Chigwedere, has insisted "people had been moved to an appropriate place", adding that there is "nobody in Zimbabwe who does not have a rural home".

But David Coltart, an MP with the opposition Movement for Democratic Change, said what had happened was nothing short of a pogrom against the government's opponents.

The state now exercises total control over media and movement inside Zimbabwe. The last two dissenting voices, SW Radio Africa and the Daily News, have been forced to close. A recent headline in The Chronicle, a government mouthpiece, told its readers that Britain was following Zimbabwe's lead and demolishing up to 400,000 homes in a similar clean-up campaign.

Foreign reporters have been expelled and millions of pounds have been spent on strengthening the secret police force, the CIO, in order to infiltrate civil society and opposition groups. In this atmosphere of intimidation and misinformation many Zimbabweans have little idea of what is happening outside their immediate surroundings.

In the hospitals of Bulawayo there are no queues to speak of. But the reason is that people are dying before they can reach a city hospital, according to Dr Mike Cotton, a consultant surgeon. "People have lost confidence in the health service. They don't believe it's worth the time and money to get to a hospital where there is little that can be done for them. They'd rather stay and die where they are," he said.

In antenatal clinics, HIV infection rates are running at 50 per cent. Tests conducted in army barracks show infection rates in excess of 80 per cent.

Zimbabwe, alone among the countries of southern Africa is seeing negative population growth. According to official figures the population stands at 12 million. A senior health official, speaking on condition of anonymity said the real figure could be as low as 9.5 million. Average life expectancy in Zimbabwe has plummeted to just 33.

In Brunapeg, Dr Porrino says: "People ask me why they should bother to be tested for HIV. They ask what I can do for them if they are infected. And I have to tell them the truth: nothing."

And the doctor has a question of his own: "Does anyone in the outside world know what's going on here? What are people waiting for?"

Lib Dems join campaign against UK deportations

Pressure is mounting on ministers to halt the deportation of failed Zimbabwean asylum-seekers amid fears of increasing violence by President Robert Mugabe's regime.

Mark Oaten. the Liberal Democrat home affairs spokesman, wrote to the Home Secretary demanding a moratorium on deportations to Zimbabwe. He said: "The Mugabe regime is wholly unsafe and plainly has no respect for human rights."

There are 116 Zimbabwean asylum-seekers in detention awaiting possible deportation, the Home Office says. Scores are on hunger strike in protest against the lifting last November of a ban on forced deportation.

The Right Rev Colin Fletcher, Bishop of Dorchester, joined the campaign, calling for a "compassionate" response to the plight of Africans who had fled the Mugabe regime. The Commonwealth secretary general, Don McKinnon, also expressed concern. He told the BBC: "It is clear the problems are there. You only deport people or send them back if you believe they are not in danger or not threatened in any way."

Hilary Benn, the Secretary of State for International Development, defended the Government's position. He told the BBC: "The asylum system has to make a judgement as to whether people are entitled to the protection of the [refugee] convention or not. We would never send anyone back if we thought that their lives were in danger."