Having previously lived in the chaotic, pot-holed shambles of Kampala, the Ugandan capital, I was astonished by how prosperous Harare appeared. The supermarkets sold everything, cinemas showed the latest films and you could drive to spacious houses in leafy suburbs along immaculate roads with functioning traffic lights - a rarity in Africa.

Getting permission to work as a journalist could not have been easier. A helpful official at the Information Ministry was pleased to provide the necessary paperwork. I was granted accreditation for three years. The paranoia that was to sweep the government lurked beneath the surface, but was not yet all-consuming.

In barely two years, I have seen Zimbabwe become another country. Watching a government wreck an entire society has acquired a certain morbid fascination. The point at which Zimbabwe's decline became a vicious spiral can easily be identified - the referendum on a new constitution last February.

Mr Mugabe suffered a crushing defeat as 55 per cent of Zimbabweans rejected his proposed draft. After listening to the results in a gloomy government ministry, filled with depressed officials, I ran to the headquarters of the National Constitutional Assembly, an opposition alliance. From the living room of a modest house, a handful of young Zimbabweans had masterminded a campaign that had inflicted on Mr Mugabe his first defeat.

Banned from state television, vilified by the official press and deprived of all but shoestring funds, they had overcome a mighty official campaign, with a budget of around £1 million. Now they celebrated, in true African style. Dancing, singing figures filled every room and spilled over into the garden. Priscilla Misihairabwi, one of the "No" campaigners, shouted: "Dictators are always beaten. The people always win in the end."

That night, Mr Mugabe broadcast to the nation. As we watched, nervous about his reaction, he graciously accepted defeat and posed, for one last time, as the father of the nation. It was a sham. Within days, Zimbabwe had entered the vortex from which it has yet to emerge.

Mobs began invading white-owned farms, ostensibly to retake land stolen by colonial rulers. At first, it all seemed peaceful. On Parklands farm near Norton, 20 miles west of Harare, I spent an entire day with a group of squatters, supposedly in the vanguard of Mr Mugabe's revolutionary struggle to wrest land from the white oppressor. One was a Manchester United fan and all were friendly. A ringleader who wore a T-shirt emblazoned with Mr Mugabe's face offered me a five-acre plot of land. I declined politely.

By March, the number of occupied farms had risen above 500 and the squatters unleashed a wave of violence. While Mr Mugabe's most die-hard critics would agree that land reform in Zimbabwe is essential, it was becoming increasingly clear that this emotive issue had become subsumed into Mr Mugabe's desperate battle to hold on to power. I travelled to Karoi, 130 miles north-west of Harare, and met Anthony and Dawn Wells, hours after their house had been stormed by an axe-waving mob, over 100 strong. Incoherent with rage, the gang's ringleader had threatened to kill Mr Wells and shouted obscenities, his breath reeking with alcohol, his eyes inflamed by drugs.

Yet I was able to meet this short, stocky figure, who styled himself Comrade Jesus. We talked beside the makeshift camp his followers were building on Mr Wells's land. Surrounded by henchmen with axes slung across their shoulders, Comrade Jesus assured me in fluent English that he had no hatred for whites and wanted nothing more than "peace and justice". Barely six weeks later, I was to meet the battered, bleeding figures of his victims and see him face two charges of murder. Needless to say, the case against Comrade Jesus was dropped and he has since been rewarded with a tobacco farm near Karoi.

By now, it was obvious that the farm invasions were a central part of Mr Mugabe's ruthless campaign to wipe out the opposition Movement for Democratic Change (MDC). The squatters, who claimed to be veterans of the war against white rule, became the shock troops of his regime. They mounted what Amnesty International called a "systematic programme of country-wide violence" - and were well rewarded for their efforts. Mr Mugabe's regime transported them from one farm to the next, supplied weapons and paid them a daily rate.

The violence entered a new phase on April 1 last year. A "march for peace", staged by the opposition to protest over the growing climate of terror, made its way through central Harare. About 200 thugs emerged from the headquarters of Mr Mugabe's Zanu-PF party and marched down Union Avenue to confront the 2,000 demonstrators, among whom were children and people in wheelchairs.

From the front rank of the march, I saw them coming. They waved sticks and clubs in the air. Many wore the distinctive uniform of so-called "war veterans" - Mugabe T-shirts, leather jackets and green caps. A volley of stones flew towards the demonstrators and, as 50 riot police stepped hastily aside, the mob charged.

Crouching in a shop doorway, I watched people flee in panic as the shopping street was overrun by anarchy. A white couple in their fifties were toppled by stones and fell to the ground. Seconds later, three thugs attacked them with clubs. I watched, transfixed, as blood spattered six feet across the pavement as the clubs rose and fell. The couple were taken to hospital.

Mr Mugabe removed any doubts about the official attitude to the mayhem. In the space of eight hours on April 15, David Stevens, a white farmer, was tortured and beaten to death. Five other landowners were abducted and narrowly escaped murder. Tichaona Chiminya and Talent Mabika, two MDC officials, were burned to death in a petrol bomb attack.

The morning after the worst violence yet seen, Mr Mugabe addressed 1,000 supporters and vigorously fanned the flames. He blamed the MDC for the murders and said: "Hit back wildly." Speaking before him, Sydney Sekeramayi, the security minister, made the message unmistakable. "The MDC have slapped a lion in the face and they will be devoured," he said.

As the parliamentary elections in June approached, being a journalist in Zimbabwe involved nothing more than interviewing the victims. In Kariba, I toured a hospital filled with shattered bodies - the results of a foray by Comrade Jesus. In Mberengwa, I met a woman who had been gang-raped in front of her eight-year-old son.

By the time election day came, human rights groups had recorded 37 murders and 18,000 examples of other abuses, ranging from assaults and torture to rape. Yet despite all this, the MDC won 57 parliamentary seats and became the most powerful opposition force in Zimbabwean history.

Since then, the regime has attacked a bewildering array of enemies, from judges and journalists to human rights activists and diplomats. The "shock troops" have also targeted businesses in Harare, terrorising local workers, and extorting money from their managers, deepening the crisis into which the economy has spiralled. Only yesterday, there was a new regulation on foreign exchange, forcing exporters to sell 40 per cent of their earnings to the Reserve Bank at the meaningless official exchange rate, a move which is certain to push many into bankruptcy.

There have also been mindless attacks on charities and even a hospital. A few weeks ago, I visited the Avenues clinic hours after it had been raided by a mob of Mugabe militants, seemingly motivated only by theft.

But these are, I hope, the dying kicks of the donkey. Last year's election delivered a crippling blow to Mr Mugabe's authority, and it is just possible that the next presidential election, due by next April at the latest, will deliver the coup de grace. Despite all the gloom over the deteriorating economy and the heightened repression, change is in the air. My only regret is that, barring a last-minute change of heart by the authorities, I will not be here to see it and witness Zimbabwe becoming once again, the country I knew when I arrived.