Ryszard Kapuscinski: He was hailed as the greatest reporter of his time. But how much did he make up?

Throughout much of the Western world, Ryszard Kapuscinski was eulogised as the most perceptive and brilliant reporter of his time. As a foreign correspondent, he claimed to have befriended Che Guevara and to have narrowly escaped death by an African firing squad. Salman Rushdie once said of him: "He is worth a thousand whimpering and fantasising scribblers."

Yesterday, however, a biography was published in Kapuscinski's native Poland which portrays much of his work as invention. Kapuscinski – Non Fiction, by the Polish journalist Artur Domoslavski, says he "consciously built on his status as a legend" and "extended the boundaries of reportage far into the realm of literature".

Domoslavski says that the journalist famed for books such as The Soccer War and Imperium never met Guevara and many other figures he claimed to have known as a globetrotting reporter. His claims that he narrowly escaped death by firing squad are dismissed as fantasy; his insistence that his father was a prisoner of war in Russia, a lie.

Kapuscinski died in 2007 a national hero, aged 74. Predictably, Domoslavski's assault has elicited a mixed if not choleric response in Poland. The former Foreign Minister Vladyslav Bartoshevski has compared the biography's publishers to "purveyors of brothel guides", and Kapuscinski's widow, Alicja, has tried in vain to have it banned.

Yet Domoslavski's work is plausible. For many years, he was both a journalistic colleague and personal friend of Kapuscinski. "He used to call me up and say Artur, come over, let's have a chat," says Domoslavski, who works for the respected liberal Warsaw daily Gazeta Wyborczca. He refers to Kapuscinski as "Richi".

Domoslavski says that his suspicions about his colleague were aroused because he habitually gave evasive answers when pressed on the details of his prizewinning books. To research his biography he was given access to Kapuscinski's private archive, but he also retraced his steps and re-interviewed several of the figures who featured prominently in his writings. His conclusion is that there were many glaring inconsistencies in his work.

Kapuscinski was born in Belarus and brought up in Communist Poland after the war. After studying at Warsaw University, he started out as a journalist on a youth newspaper before joining the Polish state-controlled news agency PAP in the late 1950s. For decades he was in the extraordinary and privileged position of being PAP's only foreign correspondent. He spent much of his time in Africa, covering the whole continent, 27 revolutions and coups. He went on to cover similar conflicts in Asia and Latin America. One of his most famous books, The Soccer War, is an account of the 1969 war between El Salvador and Honduras which was sparked by two football games. In Britain, Kapuscinski's account of the overthrow of the Ethiopian Emperor Haile Selassie, The Emperor, was turned into a play and staged at the Royal Court Theatre in London.

Yet Domoslavski comes to the conclusion that Kapuscinski manipulated his reportage to improve its dramatic effect. In his biography he quotes a well-known Ethiopian woman journalist on her opinion of Kapuscinski's account of Haile Selassie's overthrow. She replies that much of it would have looked better in Arabian Nights than in a piece of factual reportage.

Similar manipulation, according to Domoslavski, was applied in the case of Che Guevara. The fly covers of several of Kapuscinski's books about Latin America state that the journalist personally knew the revolutionary. However when asked by an American biographer of Guevara when their meeting took place, Kapuscinski admitted that the Guevara claim was "a mistake" made by his publishing house. However the publishers never removed the claim from the fly cover. Kapuscinski also continued to maintain in subsequent interviews that he had been with Guevara on dangerous missions.

Domoslavski also debunks Kapuscinski's account of his supposed encounter with Patrice Lumumba, the 1960s Congolese freedom fighter. His research shows that Kapuscinski could never have seen him in action because he made his first visit to Africa after Lumumba's assassination. He also dismisses as "self-important fantasy" Kapuscinski's claim that while in the Congo, he was rescued from a firing squad at the last minute.

The reporter's ability to massage the facts allegedly did not stop there. Domoslavski also badly dents the heroic wartime image Kapuscinski ascribed to his own father. As a Soviet prisoner of war, he was reputed to have narrowly escaped being killed in the Katyn massacre of the Second World War in which the Soviet secret police slaughtered thousands of Polish officers. In fiercely Catholic post-Communist Poland, the story seemed to prove that Kapuscinski came from a noble and patriotic family. Kapuscinski claimed that his father managed to escape from a Soviet prisoner-of-war transport. However Domoslavski maintains that his father was never a Soviet prisoner.

Later sections of Kapuscinski – Non Fiction delve into the reporter's seemingly dubious relationship with the authorities in Communist Poland. Domoslavski notes that Kapuscinski was a card-carrying Communist Party member for most of his life. His reportage from Third World countries helped at the time to convince liberal Western audiences that the region's problems were a result of Western colonialism. In that sense he helped the Communist cause.

However the extent to which Kapuscinski may have been an outright stooge of the Communist regime is only hinted at. He renounced his Communist Party membership during Poland's Solidarity era, but Domoslavski suggests that the regime may have allowed him to do this on purpose to show that it was not prepared to persecute a figure of international repute. He notes, however, that the idea of opening his secret police file induced panic.

But it is for Kapuscinski's factual reportage, frequently described as "magnificent", that Domoslavski reserves his most withering criticism. "Some of his books just don't belong on the non-fiction shelves," he says.