Updated 10pm

Brazil's leftist icon Luiz Inacio Lula da Silva walked free from jail on Friday after 18 months behind bars for corruption following a court ruling that could release thousands of convicts. 

The former president, wearing a black T-shirt and suit jacket, pumped his fist in the air as he left the federal police headquarters in the southern city of Curitiba and was quickly mobbed by supporters and journalists.

The 74-year-old is among several thousand convicts who could be freed after the Supreme Court's decision late Thursday to overturn a rule requiring convicted criminals to go to jail after losing their first appeal.

They would remain free until they had exhausted their rights to appeal their conviction - a process critics say could take years in cases involving people able to afford expensive lawyers. 

Many of those affected by the 6-5 ruling are political and business leaders caught up in a massive corruption probe dubbed Car Wash that began in 2014.

A hero to millions

Lula, who led Brazil through a historic boom from 2003 to 2010, earning him the gratitude of millions of Brazilians for redistributing wealth to haul them out of poverty, is serving eight years and 10 months for corruption.

He was sentenced to almost 13 years in jail in February in a separate corruption case and still faces another half dozen corruption trials.

Lula has denied all the charges, arguing they were politically motivated to keep him out of the 2018 presidential election that was won by far-right President Jair Bolsonaro.

Lula's lawyers said they would seek the "immediate release" of the 74-year-old leftist leader, who remains an extremely popular, albeit divisive, figure in Brazil.

A judge needs to authorize his release, which could be as early as Friday. 

"I'm coming for you, wait for me!" Lula's girlfriend, Rosangela da Silva, tweeted after the Supreme Court announced its decision. 

If he is freed, Lula's criminal record will prevent him from resuming his political career. He was the founder of the Workers Party (PT). 

But his release could simultaneously invigorate the left and help Bolsonaro, who was swept to power in 2018 on a wave of anti-PT sentiment, said Thomaz Favaro of Control Risks consultancy.

"You will have Lula more present on the political scene and that allows Bolsonaro to reinforce his role as leader of the anti-PT field," Favaro said.

Key dates in the life of one of the world's most popular politicians.

- October 27, 1945: Lula is born to a poor farming family in Brazil's northeast. His family moves when he is seven to the state of Sao Paulo to escape hunger.

- 1975: He becomes president of the metal workers' union, having worked in that sector since the age of 14.

- 1978-80: At the height of the military dictatorship, Lula leads major strikes in the industrial suburbs and is jailed for a month for his role.

- 1980: Lula co-founds the leftist Workers Party (PT) and goes on to take part in the creation, in 1983, of the Unified Workers Central (CUT), which becomes Brazil's largest trade union federation.

- 1986: He is elected to Congress.

- 2003: Lula becomes Brazil's first leftist president, and the first to originate from the working class, after winning the previous year's election. Under his social programs 29 million Brazilians escape poverty, although inequality remains. He is re-elected in 2006 for a term ending in 2010.

- 2005: He removes top officials of the Workers Party over corruption scandals.

- 2016: The Supreme Court blocks his appointment as chief of staff to President Dilma Rousseff, his handpicked successor. She is then impeached in August after allegations of financial wrongdoing.

- July 2017: Lula is found guilty of receiving a bribe from a Brazilian construction company in return for contracts with state oil giant Petrobras. He is sentenced to nine and a half years behind bars.

- January 2018: He loses an appeal and his sentence is increased to 12 years and one month.

- April 5, 2018: After losing an appeal to delay the start of his sentence, Lula is ordered to turn himself in within 24 hours. He defies the order but later agrees to comply. 

- April 7, 2018: Shortly before midnight, Lula becomes an inmate at the federal police headquarters in Curitiba. 

- August 15, 2018: Lula's Workers Party officially registers his presidential candidacy.

- August 31, 2018: A majority of Brazil's electoral court bars Lula from running in October's election.

- September 11, 2018: The Workers Party names Fernando Haddad as a substitute candidate for Lula.

- October 28, 2018: Far-right candidate Jair Bolsonaro is elected president, ending decades of center-left rule in Brazil and reducing Lula's chances of freedom.

- February 6, 2019: Lula is handed a near 13-year sentence for accepting renovation work by two construction companies on a farmhouse in exchange for ensuring they won contracts with Petrobras.

- April 7, 2019: Thousands rally to protest Lula's first year in prison. 

- April 23, 2019: A Superior Court of Justice panel reduces Lula's sentence to eight years and 10 months on appeal.

- November 7, 2019: The Supreme Court overturns a rule requiring convicted criminals to go to jail after losing their first appeal, paving the way for Lula's release.