Lula, 73, was found guilty of taking renovation work from a company implicated in a massive corruption scheme.

The former president is already serving a 12-year sentence over work done on a beach-front property.

His lawyers said he would appeal against the new conviction.

The former trade union activist and iconic figure for the left in Latin America led Brazil between 2003 and 2010.

Lula denies all the charges against him, claiming they are politically motivated and designed to stop him running for president.

What is the latest case about?

Federal Judge Gabriela Hardt said construction group OAS extensively redecorated a farmhouse which Lula frequently visited.

Lula's lawyers argued the house did not belong to him but instead to a friend, Fernando Bittar.

There have been large protests in support of and against Lula since his arrest

But Judge Hardt said the ex-leader went to the property far more than the owner and ordered the building work - which reportedly cost the company more than 1m reais (£209,000; $270,000).

"The accused received these unjustified benefits because of his position as president of the republic, of whom exemplary behaviour is demanded," she reportedly ruled.

Ms Hardt is the new head of a sprawling investigation known as Operation Car Wash - a colossal corruption probe dubbed "the largest foreign bribery case in history" by the US Department of Justice.

The former judge in charge, Sergio Moro, resigned the job last year when he took up the role of justice minister in newly-elected President Jair Bolsonaro's government.

What's the reaction?

Head of Lula's left-wing Worker's Party (PT) Gleisi Hoffmann tweeted that "the persecution of Lula continues".

Those convicted in Brazil can often be released on probation after only a third of their sentence, which means that the 73-year-old could now be behind bars for the next eight years, rather than the next four.

The former president was not allowed to leave prison last week to attend his brother's funeral.

President Bolsonaro said he hopes Lula "rots in prison" in a video address in October.

On Wednesday he tweeted news of the conviction without comment.