Che Guevara, unbending socialist revolutionary, is a global capitalist brand.

Tuesday is the 40th anniversary of his execution by CIA-backed soldiers. Venezuelan president Hugo Chavez will be among those paying tribute.

There will be small commemorations in Ireland and Britain. In the refugees camps of Gaza, which Che visited, his image is still displayed.

While it's entirely appropriate that radicals, revolutionaries and the dispossessed everywhere honour their hero, what of the others who flaunt Che's image but haven't a clue about the real man?

In 1960, a young Cuban photographer, Alberto Korda, snapped Che standing beside Castro on a balcony in Havana. In red star beret, his hair wild and free, his eyes set on some future vision, Che's appeal was obvious. It's the most reproduced image in the history of photography. He became a romantic figure, doomed to die young and beautiful.

James Dean with a dose of politics. And over the years, the politics mattered less as the romance of Che came to the fore.

Diego Maradona and Mike Tyson have Che tattoos. Thierry Henry attended a Fifa gala dinner in a Che t-shirt. Madonna, the millionaire pop star who buys black babies, dressed as Che for the cover of her album American Life.

Che would probably have shot her. That's not an exaggeration.

The man now worshipped by millions of westerners was handsome and charismatic but he was also an unshakeable militarist.

Che came to bring not peace but war. He wanted "a hundred Vietnams". He chose conflict over compromise every day. He was killed in the Bolivian mountains leading not an impressive popular front but a handful of guerrillas . . . a micro-group . . . with negligible support, carrying out isolated attacks in the hope it would inspire others to rise up.

Although a fine film, Walter Salles's TheMotorcycle Diaries, a road movie of Che's coming-ofage journey across Latin America with his best friend, Alberto Granado, overly softened the image. Filmmakers are uneasy with Che's ruthless militancy.

"Relentless killing of the enemy impels us and transforms us into effective and selective violent, cold killing machines, " he said. "I don't care if I fall as long as someone else picks up my gun and keeps on shooting."

Che, an atheist, expressed sentiments for which Patrick Pearse is so roundly condemned . . . and he was writing 50 years after Pearse. Not that Che's violence was mindless. He was sickened by the poverty he saw on his road trip with Alberto Granado. He passionately believed violence was the only appropriate response to US imperialism and its satellite states.

"We must carry the war into every corner the enemy happens to carry it: to his home, to his centres of entertainment, a total war. It is necessary to prevent him from having a moment of peace. We must attack him wherever he may be, make him feel like a cornered beast, " he said.

But he had compassion. He used his medical training personally to treat wounded enemy soldiers. He was a man of many complexities. He read Freud, was an avid photographer and he was carrying a battered book of love poems when he was killed. "Let me say, at the risk of seeming ridiculous, the true revolutionary is guided by great feelings of love, " Che said.

Ernesto Guevara . . . later called 'Che' for his habit of referring to everyone as 'che' (pal) . . . was born in 1928 to aristocratic but radical parents in Rosario, Argentina.

His battle with chronic asthma from childhood led him to believe every problem could be overcome through sheer will. Despite his illness, he was naturally athletic and a keen rugby player.

He was nicknamed 'El Furibundo' (the Raging) for his aggressive style of play. On course to enjoy life as a wealthy Argentinian doctor, he abandoned it all for revolution. In Mexico in 1956, he met Fidel Castro who was plotting insurrection against Cuban dictator Fulgencio Batista.

Che, Castro and 80 others set sail for Cuba on a rickety yacht, Granma, on the mad mission of invading Cuba. In 1958, around 300 rebels, displaying tremendous courage and skill, defeated 10,000 of Batista's men in the Sierra Maestra mountains. They took Havana the following year.

As a leader, Che was utterly ruthless. "If Christ stood in my way, I, like Nietzsche, would not hesitate to squish him like a worm, " he declared. Peasants were executed for disloyalty. "To send men to the firing squad, judicial proof is unnecessary.

These procedures are an archaic bourgeois detail, " he announced.

It is not possible to tolerate even the suspicion of treason."

As commander of La Cabana Fortress prison in Havana, he oversaw many executions of 'counter-revolutionaries'. He wasn't one for inclusiveness and bridge-building. President Gamal Abdel Nasser recalled Che asking him how many people had left Egypt because of land reform.

Che was disappointed when Nasser replied no one. The way to measure true change was by the number of people "who feel there is no place for them in the new society", he said.

He held several senior positions in the new administration, even governor of the National Bank, though by mistake. "Is there an economist in the room?"

someone had asked at a ramshackle meeting of the victorious revolutionaries. To much amazement, Che stuck up his hand and so became bank governor. He had misheard the question as, "Is there a communist in the room?"

Che could have settled into a comfortable, bureaucratic job.

But he had no lust for power and, once again, politics led him to the harsher path. He was disappointed in the Soviet Union at failing to support revolutionaries abroad and he was increasingly at odds with Castro who chose to concentrate on building Cuba.

Che wanted international revolution. In 1965, he set off . . .

first for the Congo, later Bolivia.

Castro wrote of Che's way "in every difficult and dangerous moment, of doing the most difficult and dangerous thing".

There are uncorroborated claims Castro heard of the CIA plot to kill Che in Bolivia and did nothing. The Bolivian soldiers who captured Che drew straws for the 'honour' of killing him on 9 October 1967. It was a brutal end.

Wanting his face unmarked so the identity of the corpse would not be in doubt, there were to be no bullets to his head but many to his body. "Shoot coward, you are only going to kill a man, " Che shouted at his executioner. He was 39 years old and left behind five children from two marriages.

His hands were cut off afterwards and his body laid out on a table and photographed for the world to see. It was the universal image of the martyr, like Christ in a Mantegna painting. He was given an anonymous burial on a Bolivian airstrip but, in 1997, his remains were recovered. They now lie in a mausoleum outside the Cuban city of Santa Clara.

Had Che not been good-looking and died young, he would be forgotten or mocked. Old or ugly men preaching revolution are ridiculed. Not that he would have minded. "It's a sad thing not to have friends, but it's even sadder not to have enemies, " he wrote.

His most striking characteristic was that, unlike other revolutionary and mainstream military leaders, he didn't send others out to die without constantly putting himself in the firing line as well.

"Many will call me an adventurer and that I am, only one of a different sort: one who risks his skin to prove his platitudes."

Again, unlike other modern guerrillas, in Ireland and abroad, Che never tried to mask his own ruthlessness in conflict. He was brutally honest, laying it bare in his writings. He is no fashion icon. The historical truth about him is vital. It's on his actions he should be judged. Che Guevara is much more than just a face on a poster.