They were always portrayed as victims of fascism, but Mussolini’s soldiers committed atrocities which for 60 years have gone unpunished. Now the conspiracy of silence is at last starting to unravel

The footnotes of Italian history record Giovanni Ravalli waging war on criminals. He was a police prefect who kept the streets safe and pursued gangs such as the one which stole Caravaggio's The Nativity from a Palermo church in 1969. An adviser to the prime minister, a man of the establishment, he retired on a generous pension to his home at 179 Via Cristoforo Colombo, south Rome, to tend his plants and admire the view. He died on April 30 1998, aged 89.

The footnotes do not record a Greek policeman called Isaac Sinanoglu who was tortured to death over several days in 1941. His teeth were extracted with pliers and he was dragged by the tail of a galloping horse. Nor do they mention the rapes, or the order to pour boiling oil over 70 prisoners.

After the war Ravalli, a lieutenant in the Italian army's Pinerolo division, was caught by the Greeks and sentenced to death for these crimes. The Italian government saved him by threatening to withhold reparations unless he was released. Ravalli returned home to a meteoric career that was questioned only once: in 1992 an American historian, Michael Palumbo, exposed his atrocities in a book but Ravalli, backed by powerful friends, threatened to sue and it was never published.

His secrets remained safe, just as Italy's secrets remained safe. An audacious deception has allowed the country to evade blame for massive atrocities committed before and during the second world war and to protect the individuals responsible, some almost certainly still alive. Of more than 1,200 Italians sought for war crimes in Africa and the Balkans, not one has faced justice. Webs of denial spun by the state, academe and the media have re-invented Italy as a victim, gulling the rest of the world into acclaiming the Good Italian long before Captain Corelli strummed a mandolin.

In reality Benito Mussolini's invading soldiers murdered many thousands of civilians, bombed the Red Cross, dropped poison gas, starved infants in concentration camps and tried to annihilate cultures deemed inferior. "There has been little or no coming to terms with fascist crimes comparable to the French concern with Vichy or even the Japanese recognition of its wartime and prewar responsibilities," says James Walston, a historian at the American University of Rome.

The cover-up lasts to this day but its genesis is now unravelling. Filippo Focardi, a historian at Rome's German Historical Institute, has found foreign ministry documents and diplomatic cables showing how the lie was constructed. In 1946 the new republic, legitimised by anti-fascists who had fought with the allies against Mussolini, pledged to extradite suspected war criminals: there was a commission of inquiry, denunciations, lists of names, arrest warrants. It was a charade. Extraditions would anger voters who still revered the military and erode efforts to portray Italy as a victim of fascism. Focardi's research shows that civil servants were told in blunt language to fake the quest for justice. A typical instruction from the prime minister, Alcide De Gasperi, on January 19 1948 reads: "Try to gain time, avoid answering requests."

Yugoslavia, Greece, Albania, Ethiopia and Libya protested to no avail. "It was an elaborate going through the motions. They had no intention of handing over anybody," says Focardi. Germans suspected of murdering Italians - including those on Cephalonia, Corelli's island - were not pursued lest a "boomerang effect" threaten Italians wanted abroad: their files turned up decades later in a justice ministry cupboard in Rome.

Britain and the US, fearful of bolstering communists in Italy and Yugoslavia, collaborated in the deception. "Justice requires the handing over of these people but expediency, I fear, militates against it," wrote a Foreign Office mandarin. The conspiracy succeeded in frustrating the United Nations war crimes investigation. There was no Nuremberg for Italian criminals.

Given the evidence against them, it must rank as one of the great escapes. General Pietro Badoglio's planes dropped 280kg bombs of mustard gas over Ethiopian villages and strafed Red Cross camps. He died of old age in his bed, was buried with full military honours and had his home town named after him. General Rudolfo Graziani, aka the butcher of Libya, massacred entire communities; his crimes included an infamous assault on the sick and elderly of Addis Ababa. His men posed for photographs holding severed heads. General Mario Roatta, known to his men as the black beast, killed tens of thousands of Yugoslav civilians in reprisals and herded thousands more to their deaths in concentration camps lacking water, food and medicine. One of his soldiers wrote home on July 1 1942: "We have destroyed everything from top to bottom without sparing the innocent. We kill entire families every night, beating them to death or shooting them."

Italy's atrocities did not match Germany's or Japan's in scale and savagery, and it is no myth that Italian soldiers saved Jews and occasionally fraternised with civilians. Glows of humanity amid the darkness; yet over time they have suffused the historic memory with blinding light.

The distortion can partly be blamed on British prejudices about Italian soldiers being soft and essentially harmless, says Nic Fields, a military historian at the University of Edinburgh: "Many British historians liked to focus on the luxury items found in Italian barracks. It reinforced the image of opera buffoons. Your average Tommy tended to caricature the Italians as poor sods caught up in the war."

The crimes have been chronicled in specialist journals but never became part of general knowledge. Ask an Italian about his country's role in the war and he will talk about partisans fighting the Ger mans or helping Jews. Ask about atrocities and he will talk about Tito's troops hurling Italians into ravines. Unlike France, which has deconstructed resistance mythology to explore Vichy, Italy's awareness has evolved little since two film-makers were jailed in the 1950s for straying off-message in depicting the occupation of Greece.

When Japanese or Austrians try to gloss over their shame there is an outcry, but the Italians get away with it. The 1991 film Mediterraneo, about occupiers playing football, sipping ouzo and flirting with the locals on a Greek island, was critically acclaimed. Captain Corelli's sanctification of Italian martyrdom was not challenged. Ken Kirby's 1989 BBC Timewatch documentary, Fascist Legacy, detailing Italian crimes in Africa and the Balkans and the allies' involvement in the cover-up, provoked furious complaints from Italy's ambassador in London. The Italian state broadcaster, Rai, agreed to buy the two one-hour programmes, but executives got cold feet and for 11 years it has sat in a vault in Rome, too controversial to broadcast. "It's the only time I can remember a client shelving a programme after buying it," says a BBC executive.

Kirby did manage to show it at a film festival in Florence. The reaction was toxic. "They put security on me. After the first reel the audience turned around and looked at me, thinking 'what a bastard'."

A brief storm of publicity engulfed Michael Palumbo, the documentary's historical consultant. "I was practically assaulted by several Italian journalists. There was a sackful of death threats, some from former soldiers."

The documentary gave a voice to Italian historians such as Giorgio Rochat, who have provoked disapproval from colleagues by attacking the myth. "There remains in Italian culture and public opinion the idea that basically we were colonialists with a human face."

Another historian, Angelo Del Boca, says those guilty of genocide were honoured. "A process of rehabilitation is being organised for some of them by sympathetic or supportive biographers." He says that for decades his research was obstructed - an accusation echoed by Focardi. Vital documents are "mislaid" or perpetually out on loan. Just one example: 11 years ago a German researcher found documents and photographs of Italian atrocities in Yugoslavia in the central state archive, a fascist-built marble hulk south of Rome. No one has been able to gain access to them since.

Such scholars are few, but thanks to their work a tentative reappraisal may be under way. While paying homage last march to the Italian troops massacred by Germans on Cephalonia, President Carlo Azeglio Ciampi, noting that Italy invaded Greece, asked forgiveness. Newspapers such as La Stampa and Manifesto have reported new research, and a weekly magazine, Panorama, confronted Ravalli before he died. But Italy remains entranced by its victimhood. Television commentary for a military parade in Rome earlier this month hummed the glory and sacrifice of the armed forces. Newspapers splashed on the possibility that a 92-year-old former Nazi SS officer living in Hamburg, Friedrich Engel, may be prosecuted for crimes in Genoa. Other former Nazis accused of murdering Italians are being pursued now that the fear of a "boomerang" effect against Italian criminals has evaporated.

Last month workers digging in northern Ethiopia stumbled on yet another Italian arms depot suspected of containing mustard gas. Addis Ababa asked Rome to respect an international weapons treaty by revealing the location of stockpiles and helping to clear them. Like all other requests over past decades, it was rebuffed. "All efforts on Ethiopia's side to convince Italy to live up to its responsibilities have failed," lamented the government.

That week Italy's media did indeed delve into the evils of fascism: Italians forced to work in Adolf Hitler's factories were campaigning for compensation.