Joaquin Hernandez Galicia: Oil workers' leader who became rich and powerful but fell foul of president he made the mistake of crossing

'La Quina' holds up a lawsuit filed against the head of Mexico's state-run oil company in 2005 (AP)

As union leader at Mexico's mighty state-run Pemex oil company for three decades, Joaquin Hernandez Galicia, better-known by his nickname "La Quina" (a play on his Christian name), was one of Mexico's most powerful men, perhaps the epitome of the corruption-ridden, virtual one-party rule which his compatriots lived through for most of the 20th century.

He was one of what were known as "the dinosaurs" – those within the circle of power – and was something of a Godfather figure; those who crossed him had a tendency to disappear, or at least suffer a severe downturn in their well-being. Union workers' wives would go to him to ask him for loans or to have his men beat up their husbands if they stumbled out of bars. The Mexican daily Excelsior recently estimated his wealth at more than $3.3bn, including foreign bank accounts, property and ranches, a figure which must surely impress British or any other union leaders around. He replied that he was probably worth a mere $167m.

Given the importance of Pemex (Petroleos Mexicanos) to what would otherwise have been considered a Third World nation, La Quina was, at his peak, arguably the most powerful man in the country, including the presidents with whom he worked, all from the long-ruling Institutional Revolutionary Party (PRI) to which his and all Mexican unions are attached. Patronage and intimidation were the best-known double act in the PRI, the politicians, the unions, the police force, indeed almost all institutions.

That power worried one of those presidents, Carlos Salinas de Gortari. He took office in December 1988 and in January 1989 ordered La Quina's arrest on charges including the killing of a federal agent by his bodyguards and illegal distribution of powerful weapons. As his bodyguards were more like a private army, Salinas had Mexican troops blow down the outside door of his home with a bazooka. Inside they found hundreds of automatic weapons – Soviet AKs, US MI6s and Nato G3s.

Salinas had been angered by La Quina's withdrawal of unconditional support for the PRI, and therefore of Salinas himself, during the 1988 election. The union boss's move, influencing the 200,000 Pemex oil workers and with a knock-on effect on other unions, almost cost Salinas victory. He won by a fraction over 50 per cent of the vote in an election that was widely seen by his opponents as fraudulent.

On election night, the vote-counting computer system – controlled by the ruling PRI under the system of the time – mysteriously collapsed while Salinas's left-wing opponent Cuahtémoc Cardendas, whose father, Lazaro Cardenas, had created Pemex as a state industry in 1934, was leading. By the time the computers came back up, Salinas was narrowly in the lead. To this day, "se cayó el sistema" [the system fell down] is a catchphrase used sarcastically by Mexicans whenever something simple goes wrong in their lives.

La Quina, who insisted the charges were trumped up, was sentenced to 35 years and spent more than eight in jail – Amnesty International misguidedly declared him a prisoner of conscience – before he was released in 1997. He was not involved, at least openly, in union affairs or politics thereafter.

He was born in 1922 in Tampico in the state of Tamaulipas on the Gulf of Mexico two years after the end of the decade-long revolution of Pancho Villa and the peasant leader Emiliano Zapata. He was of slight build, his features more strongly Mayan or Aztec than colonial Spanish or even mestizo, and the son of an oil worker at Pemex. By 1958 he was in charge of the mighty oil workers' union, an integral part of the PRI system which allowed opposition parties to exist in name to avoid being compared with dictatorship or communism.

With armed bodyguards, La Quina built a reputation for making people offers they could not refuse. In 1977 he was accused of ordering the killing of a local oil union leader, Heriberto Kehoe Vincent, who had been talking of breaking up the "mafia petrolera". Charges were dropped by a judiciary also PRI-controlled.

After La Quina's demise, Salinas and the PRI had their own problems: Salinas's successor Ernesto Zedillo accused him of ruining the country's economy, but not his own pocket. Ostracised, Salinas fled into exile in Ireland although he now returns to Mexico. His brother, Raul Salinas de Gortari, spent 10 years in prison for murder but was acquitted after appeals. He did lose his nest-egg – over $100m in Swiss bank accounts, which he had somehow assembled as a civil servant. Whether from fame or fear, neither Carlos nor Raul are seen strolling down the laterales of Mexico City without half a dozen armed bodyguards.

Mexico lindo [beautiful Mexico] has changed since the turn of the millennium. The PRI lost an election in 2000 for the first time in 75 years but cleaned up its act, was re-elected last year and is trying to establish its credentials as a party of democratic ideals. Its unions, however, long used to preferential treatment, remain a problem. "Pemex was a latrine of corruption before La Quina came in, but he turned it into a sewer of corruption," George W Grayson, a Mexico expert, said. "And it still is. La Quina's Croesus-like wealth and perceived political clout gave him the image as an 'untouchable.' Only President Carlos Salinas realised the cancer that he represented."

Phil Davison

Joaquin Hernandez Galicia, union leader: born Tampico, Mexico 12 August, 1922; married Carmen Correa de Juarez (three sons, one daughter); died Tampico 11 November 2013.