On April 6, 1994, headteacher Kalisa Deo was on holiday. Instead of being in Rwanda’s capital, Kigali, he was with relatives 80 miles away. Otherwise, he is convinced, he too would be among the estimated one million people murdered in a three-month killing spree which has made this central African country infamous for one of the worse instances of genocide this century.

On that fateful day, when the shooting down of a plane carrying the country’s president, Juvenal Habyarimana, marked the start of a coup by government extremists, Muhima primary school was in the middle of a public holiday. Most of its pupils, aged seven to 14, and teachers were at home with their families in the bustling suburb of Nyarugenge.

The reign of terror, which ended in early July when the victorious Rwandan Patriotic Front army seized the capital, began as a reaction to a United Nations’ peace agreement. The agreement, brokered the previous autumn, was intended to end a four-year-old war and 20 years of rule by the Hutu-dominated National Revolutionary Movement for Development (MRND), and to usher in multi-party elections.

The extremist take-over unleashed a ruthless and well-organised militia, the interhamwe, which set out to annihilate the minority Tutsi population - about 15 per cent of Rwanda’s seven million inhabitants - together with any political opposition within the Hutu community. Most were armed only with pangas (machetes), which they used with sickening brutality. Wherever they met organised resistance, however, they were able to call in Government troops with rifles and grenades.

Tutsi families were identified in several ways. Notoriously, all Rwandans were required to carry identity cards giving their ethnic origin, used among other things to ensure a rigid quota system designed to ensure that traditionally better educated Tutsi families did not gain more than their fair number of places for their children in the country’s highly selective secondary boarding schools.

Families were also identified to the interhamwe death squads by neighbours or colleagues or by employers. According to the human rights group, African Rights, a “disproportionate” number of school inspectors and directors (heads) helped to organise and participate in massacres. It has identified 25 such teachers and inspectors in a single district, Rukara. A leader of the massacre of thousands of people who sought refuge in the churches of St Famille and St Paul’s in Kigali, two of the worst atrocities, is alleged to be the woman director of a local primary school.

The group, which has interviewed hundreds of survivors of the genocide, says that in some cases teachers murdered children who attended their own classes.

According to Kalisa Deo, none of the 30 or so teachers at Muhima school was involved with the interhamwe. But like every school in Rwanda, the appalling tragedy has left deep scars. Two women teachers were murdered, and many pupils also lost their lives. Such is the awesome scale of the tragedy, however, that no one really knows how many because of the huge shifts in population since the killings began. Apart from the million dead, the great majority civilians, there are an estimated two million refugees, overwhelmingly Hutu, in neighbouring countries, principally Zaire and Tanzania, and hundreds of thousands internally displaced after fleeing their home communities.

Among those who fled the country are an unknown number of children from Muhima school and their families. The picture is further confused by the influx of new pupils since the war, many from Tutsi families who fled Rwanda in previous persecutions. Of the 1,905 children now attending school, 306 lost both their parents in the slaughter. A further 492 lost fathers.

The turnover of teachers at Muhima primary also reflects the scale of upheaval, with a number reported to have fled to refugee camps over the border. While many moderate Hutus welcomed the Tutsi-dominated liberators, who brought an end to the genocide and a commitment to democracy, many more feared retribution. In the country as a whole, only 30 per cent of teachers in post before last April are still there. The rest have been killed, fled, or simply disappeared.

In many cases schools, like churches, were sought out as sanctuaries at the height of the killings, only to become the scene of some of the biggest massacres. Orphanages, children’s homes and homes for disabled children were also targets for extremist attack. At a school in Kibeho in the southern province of Gikongoro, 88 children were reported to have been killed. Witnesses claimed a local priest first separated Tutsi and Hutu pupils.

Muhima primary school was not used as a refuge. Outside its gates, however, the interhamwe set up a road block to pick up Tutsi families or Hutu dissidents attempting to flee the terror. This was the scene of many killings. In the red clay playground a large pit was dug as a mass grave.

Teachers were sought out by former pupils who took part in the killings. One teacher survived the systematic slaughter at St Famille church, while another was hidden by a friend - at great personal risk - until the RPF took the capital.

Inevitably, many of the children at Muhima are still severely traumatised. Many witnessed or heard people being murdered, often their own parents, relatives or friends and most were forced to hide, sometimes for weeks or months, during the reign of terror.

The school, which was among the first to reopen last September, just weeks after the new RPF-led Government came to power, is facing problems almost unimaginable to a Westerner. It has no textbooks, no pictures, many of its windows and some buildings are still smashed. Despite depopulation in the country as a whole, it is suffering acute overcrowding, in part because of the influx of Tutsi refugees from Uganda and Burundi, and a shortage of teachers.

But perhaps the biggest educational problem is the children themselves. According to Kalisa Deo, they find it difficult to concentrate on their work. Many come to school hungry and go home with nothing to eat, he says.

With so many orphans, so many families slaughtered, the prospects for the immediate community are bleak for the foreseeable future. In one of the world’s poorest countries, where even before the war economic output per head of population was just Pounds 180 a year, Muhima primary school - and Rwanda’s entire education system - has little to look forward to.

Rwanda: Death, Despair and Defiance, published by African Rights, London.