SAO PAULO — Thousands of Brazilians demonstrated on Tuesday in favour of prison for former president and election frontrunner Luiz Inacio Lula da Silva on the eve of a Supreme Court ruling on whether he should start serving a 12 year sentence for corruption.

Up to 20,000 people turned out after work in the country’s biggest city Sao Paulo, as well as a few thousand in Rio de Janeiro and smaller numbers in other cities.

They demanded that Lula begin his sentence and be barred from the October 7 presidential election in which the veteran leftist is leading in the polls, despite his legal problems.

Smaller demonstrations in favour of the Workers’ Party founder also took place around the country.

The court showdown scheduled in the capital Brasilia on Wednesday has become a focal point for Brazil’s deeply divided electorate.

Lula, 72, was sentenced to 12 years and one month in prison after being convicted last year of accepting a seaside apartment as a bribe from a huge construction company seeking government contracts. He appealed in a lower court but lost.

Under current law, that means he should go immediately to prison, while conducting further appeals. However, Lula has asked the Supreme Court to grant him habeas corpus recourse, allowing him to remain free while pursuing those appeals.

The court is believed to be evenly split on the issue, so that one judge changing position would enough to secure Lula’s freedom -- and boost his uphill bid for a third term in office.

If the court turns him down, he could face jail this week.

On Monday, more than 5,000 judges and prosecutors signed a petition against granting Lula his habeas corpus request. The Supreme Court chief justice, Carmen Lucia, received 10,000 emails from Brazilians on Tuesday alone, local media reported.

Prosecutor General Raquel Dodge said that allowing convicted criminals to stay free pending several appeals would "annihilate" the justice system.

However, one of the 11 Supreme Court justices, Gilmar Mendes, tried to reassure the nation, saying the court’s ruling -- whichever way it went -- would lead to "a calming down, not an increase in conflict."

Lula is not the only major Brazilian politician in trouble this week.

Current center-right President Michel Temer, who already faces two corruption charges, is embroiled in new controversy following the arrests of several close associates on graft charges.

They were charged last Thursday in connection with the "Car Wash" probe into whether port logistics company Rodrimar was given contracts at Sao Paulo’s huge Santos port after bribing Temer.

A third charge against Temer could be announced, although as long as he is in office he faces little risk of prosecution. — AFP