BRASILIA (Reuters) - Brazil’s Supreme Court on Thursday delayed until next month a ruling on whether defendants should go to prison after losing their first appeal, a decision that could release ex-President Luiz Inacio Lula da Silva who was jailed last year for taking bribes.

The 11-member tribunal is expected to vote 6-5 in favor of overturning a rule that convicts start serving their sentences after losing their first appeal and instead allow them to exhaust the lengthy appeals process before serving prison time.

Voting stood at 4-3 in favor of keeping the rule when the court suspended the hearing on Thursday until Nov. 6.

Ending the three-year rule could lead to the freeing of Lula and dozens of other politicians and businessmen convicted in Brazil’s biggest-ever corruption investigation, the so-called Car Wash operation, until they have exhausted the appeals process.

In a swing vote on Thursday that could make that possible, Justice Rosa Weber voted to end the mandatory imprisonment rule that she had supported in the past.

Such a revision would come at a time when politicians are pushing back against the Car Wash investigation. Its team of prosecutors have come under increasing criticism for excessive use of temporary arrests and plea bargaining to obtain evidence.

The prospect of serving immediate prison time after losing a first appeal encouraged suspects to negotiate plea deals with prosecutors, providing them with information that helped unravel the biggest graft scheme in Brazil’s history centered on engineering contracts with state companies, in particular state-run oil giant Petroleo Brasileiro.

Former judge Sergio Moro, who handled most of the Car Wash trials and is now justice minister in the government of right-wing President Jair Bolsonaro, said scrapping the rule would be a major setback for Brazil’s fight against corruption.

“The legal process in Brazil is extremely slow, there are endless appeals after appeals after appeals,” Moro said at an event in Sao Paulo.