A new biography written by the woman who inherited Kwame Nkrumah's will, the Australian-born June Milne, throws more light on how Nkrumah met his end. June, now 79, met Nkrumah in 1957 and worked closely with him, first as his research assistant and then his publisher. She was with him in Romania when he died in 1972. Osei Boateng reports.

"Mr President, I have bad news. There has been a coup d'etat in Ghana", the Chinese ambassador in Accra who had gone ahead to Beijing to meet Nkrumah had the difficult task of breaking the news to the Ghanaian president soon on his arrival in the Chinese capital on 24 February 1966.

Nkrumah was on a peace mission to Hanoi, Vietnam, at the invitation of President Ho Chi Minh who wanted a peaceful way out of the war with America.

"Nkrumah was taking a brief rest after the long flight from Rangoon [Burma]. For a moment he thought he might have misheard the ambassador," writes June Milne, in the just published Kwame Nkrumah - A Biography.

It was the first, and bloodiest, coup ever in the history of Ghana. No one knows the exact figures, but it is estimated that 1,600 were killed on both sides, and many hundreds more wounded. As June puts it: "whatever the exact figure, it was far from the 'bloodless coup' reported in the British press."

Though the coup took Nkrumah by surprise, the storm clouds had actually been gathering long before he left Accra. His belief in socialism and his radical pan-Africanism was hated in the West.

In hindsight, socialism was a mistake, especially after the fall of the Berlin Wall in 1989 and the disintegration of the Soviet empire. But in the heady days after independence, with the exploitation of colonial rule just behind them, and seeing how socialism had transformed the Soviet Union into a superpower in just 40 years of the Russian Revolution of 1917, the founding fathers of Africa could perhaps be excused for believing that salvation lay in socialism.

Nkrumah's other problem was his drive for an African union government. His setting up of training bases in Ghana for African freedom fighters and political refugees from South Africa, Rhodesia, Mozambique, Angola, Guinea Bissau, etc. - a programme which saw nationalist leaders such as Sam Nujoma (Namibia), Robert Mugabe (Zimbabwe), Kenneth Kaunda (Zambia), Kamuzu Banda (Malawi), Franz Fanon (Algeria) and many more, either visiting or living in Ghana - added to Nkrumah's troubles with the West. A strong, united Africa with a strong voice in world affairs, and able to look after its own matters was considered bad news by the metropolitan powers.

As Nkrumah himself wrote after his overthrow: "They want to destroy me and Ghana for we are in the forefront of the African struggle for emancipation".

But the last straw, June Milne reveals, was the publication in 1965 of Nkrumah's book, Neo-colonialism - The Last Stage of Imperialism in which he exposed the workings of international monopoly finance. "The US government regarded the book as a hostile, dangerous statement which justified instant retaliation. There were angry diplomatic exchanges ... and $35m of American aid to Ghana was cancelled."

From then on, Nkrumah's days in government were numbered. According to revelations in books written by former CIA operatives, the budget of the CIA station in Accra was increased so Nkrumah could be kicked out quickly.

They even changed the white American ambassador in Accra and brought in an African-American, Franklin H. Williams, to take his place. Ambassador Williams was Nkrumah's mate at Lincoln University (the class of 1941). After the coup, Nkrumah wrote critically in his book, Dark Days in Ghana, about the betrayal of his former school mate - an accusation which disturbed Ambassador Williams greatly.

On 21 July 1969, Dr Marvin Wachmann who was about to leave as president of Lincoln University, wrote to Nkrumah thus: "As I prepare to leave, I would like to write a word on behalf of Franklin H. Williams of the Class of 1941... Mr Williams is a very bouncy and vigorous individual, and I have never seen him so crushed as he has been, concerning your feelings that he was involved in some way in the episodes in Ghana. He has assured me, personally, that he had no knowledge of the coup."

Nkrumah was not very amused with the denial, and as he told June Milne, "it [is] extremely unlikely that Williams did not know what was going on in the embassy with CIA officers operating from there."

June herself adds in her latest book: "It is now generally accepted that the CIA was involved in planning the coup. This involvement has been confirmed in a book, In Search of Enemies, written by a former CIA officer, John Stockwell, published in 1978. He disclosed that the CIA station in Accra 'was given a generous budget and maintained intimate contact with the plotters as a coup was hatched... Inside CIA headquarters [in America], the Accra station was given full, if unofficial credit for the eventual coup.' The CIA station chief in Accra, Howard T. Bane, was rewarded with promotion to a senior position in the Agency."

But the success of the coup depended on Nkrumah being away from Ghana, and the Hanoi peace mission offered a perfect opportunity. The mission had first been broached by the Commonwealth Prime Ministers' Conference in 1965 but it fizzled out because the British prime minister, Harold Wilson, wanted to lead the delegation, instead of Nkrumah who was the only leader acceptable to Hanoi.

President Ho Chi Minh thus sent a personal invitation to Nkrumah to lead another delegation. Nkrumah had recently engineered almost single-handedly the expulsion of apartheid South Africa from the Commonwealth, and his stock as a world leader was quite high at the time.

As he prepared to go to Vietnam in July 1965, Ho Chi Minh informed him that his security in Hanoi could not be guaranteed unless the Americans stopped the bombing of Vietnam. In August, Nkrumah sent his foreign minister Quaison Sackey to Washington to ask President Lyndon Johnson to order a halt to the American bombing so he could go to Hanoi.

That was like Saddam Hussein asking American permission to invade Kuwait. The CIA was fast at work in Accra, and Nkrumah's Hanoi mission could not have come at a better time. To lure him away, President Johnson assured Nkrumah that he would be perfectly safe in Hanoi, and that Ho Chi Minh "was only making excuses".

Three weeks to Nkrumah's departure, according to June Milne, "President Johnson sent an emissary, Menon Williams, to Accra to encourage Nkrumah to go. The CIA plans for the coup depended on Nkrumah being out of Ghana at the time."

So off, Nkrumah went - on 21 February 1966. Two days later, the coup happened!

A few months later, the newspaper Egyptian Gazette revealed in Cairo that one Amihia, a man from Nkrumah's own Nzima tribe, who was the go-between for the CIA and the local coup plotters had been killed after the coup because "he knew too much".

"I have information from a highly reliable source," Nkrumah himself wrote on 2 November 1968 to Mrs Shirely DuBois, wife of W.E.B DuBois, who had sent him the cutting from the Eygptian Gazette, "that Amihia was killed by the NLC [the military junta] because he knew too much, and they feared he might speak out."

A year later when President Eyadema of Togo went to visit the NLC in Ghana, June Milne reveals that "he was shown the Volta Dam and factories. He asked: 'who did all this?' Everything they looked at, they had to reply that Nkrumah did it. Eyadema got angry and asked: 'Why then did you do this coup? There was no need for a coup'. Relations became strained, and the state dinner arranged in his honour was cancelled."

From Beijing, Nkrumah accepted an invitation from President Sekou Toure of Guinea to come and live in Conakry. He had received similar invitations from Presidents Julius Nyerere of Tanzania, Modibo Keita of Mali and Abdel Nasser of Egypt, but he chose Conakry because it was nearer Ghana where he hoped to return to power soon.

"He had arrived in Conakry", writes June Milne, "with funds provided by the Russians when he passed through Moscow en route from Hanoi to Conakry. Later, the Chinese gave him some. Then Presidents Milton Obote of Uganda and Nyerere sent envoys carrying diplomatic bags containing cash. Both wanted to see Nkrumah back in Accra, and were realistic enough to know that this was unlikely to be achieved without money.

"Nkrumah had no funds in foreign bank accounts, and his account in Barclays Bank in Accra into which his presidential salary had been paid, was frozen by the NLC. He was therefore entirely dependent on the generosity of political friends...

"Apart from those who asked for money to carry out plans to restore [his] government...Nkrumah faced considerable expense in providing for the needs of his entourage. Board and lodging was provided by the Guinean government. But Nkrumah paid the Ghanaians a weekly wage, half of what they had earned in Ghana, the understanding being that they would receive the other half of their pay, made-up in full, on their return to Ghana."

But that was not to be. Nkrumah had stepped up his writing in Conakry, and had understandably attracted a lot of interest from Western intelligence agencies. His letters were interfered with, the ring of people around him was infiltrated with spies, his residence Villa Syli was attacked during a Portuguese invasion of Conakry and a boat full of Ghanaian would-be assassins sent from Accra was seized near Villa Syli.

Nkrumah survived it all, until his loyal cook, Amoah, who travelled with him everywhere, died on 20 July 1967.

Nkrumah liked his fufuo, the staple food of most Ghanaians. But when Amoah died, according to June Milne: "Nkrumah was obviously exposed to greater personal danger... Madame Sekou Toure recommended a cook to replace Amoah, but it was not long before he left, and after that there was a succession of Guinean cooks... When I did go [into the kitchen one day], I realised the hopelessness of ever being 100% certain that his food was safe. Apart from the cook, there were so many men working there, and others wandering in and out all the time... At times when Nkrumah occasionally seemed to suffer from digestive trouble, I began to fear for his health."

June continues: "Towards the end of one of my visits to Conakry, when I had shared all meals with Nkrumah, I developed severe stomach pains and fever. For over six weeks on my return to London, I was seriously ill with typhoid-like symptoms which mystified my doctor. Exhaustive tests at the London School of Tropical Medicine failed to produce an explanation. Health officers visited my home to inspect taps and drains, but could find nothing to identify my illness."

Nkrumah's health deteriorated gradually. First it was a Russian doctor who treated him. He said Nkrumah was suffering from acute lumbago (a disease that causes pain in the lower back, the region between the lowest ribs and the hipbones).

President Sekou Toure and other friends implored Nkrumah to go abroad for medical treatment, but he was reluctant to go lest he discouraged the Ghanaians working for his return to power.

But later, in 1969 and 1970 when his health worsened, he asked the Soviets twice to allow him to come over for medical treatment. They wouldn't allow him, instead they sent two specialists to Conakry to examine him. "They advised that there was no cause for concern, and that it was politically an 'inopportune' time for him to leave Guinea," writes June Milne.

"I was not in Conakry when the specialists arrived," she continues, "but Nkrumah wrote the day they left to tell me the outcome of their visit... Whether or not on the specialists' advice I do not know, but there followed a course of injections administered by a Bulgarian doctor.

"The nature of the injections is unclear, but in 1971 when Nkrumah was in hospital in Bucharest [Romania], the consultant there [Dr Maderjac] told me that he had been given the 'exact opposite' of the treatment he required, causing whatever he suffered from - they would not give it a name - to 'spread to his whole body'. Nkrumah's [first] son, Francis, a highly-qualified doctor, told me when I visited Ghana briefly in 1972, that there was 'inexplicable medical bungling in Guinea'.

"It seems inconceivable that the Russian specialists did not know that Nkrumah was seriously ill when they examined him in 1970," June Milne adds. "I suspect they did not want to offend the Busia regime in Ghana by inviting Nkrumah to the Soviet Union. The Russians had recently reopened their embassy in Accra. At that time they probably did not want him to return to power in Ghana. They disapproved of [Nkrumah's] Revolutionary Handbook, and his ideas on the need for armed struggle. For some time, even before 1966, they were concerned about what they saw as Nkrumah's leaning towards the Chinese and Vietnamese. There was much tension then between the Soviet Union and China."

By the beginning of 1971, Nkrumah's health had become so bad that he had to go abroad for treatment. "When at length, in August 1971, he was finally compelled to go," says June Milne, "he was carried on a stretcher into the curtained-off front section of the Aeroflot plane which was to take him to Bucharest."

Dr Maderjac who treated him in Bucharest told June that "if Nkrumah had been in his care two years earlier, a simple operation could have cured him".

Finally, the end came at 8.45 am on 27 April 1972. The man who in good health had weighed 75 kilos had been reduced to under 57 kilos by the disease. And he died.

"There was no post-mortem," June Milne reveals. "One thing is, however, certain: he would not have died when he did, in his 60s, if it had not been for the 1966 coup in Ghana. If that had not occurred, he would not have been subjected to the strains, and exposed to security risks, for example over the preparation of his food while in Guinea. His doctors in Ghana would have detected any early signs of illness, and he would have had instant treatment of the highest quality."

In 1992, after 20 years of dithering by various Ghanaian governments, a massive mausoleum was finally built in Accra for Nkrumah by the Rawlings government, shaped like "a giant tree with a fluted base, the top cut off like a half-felled tree". At last, Nkrumah, "the tree cut short", had been accepted by his own people.

The mausoleum stands on the very same spot where on 6 March 1957, he had proclaimed Ghana's independence.