The former film star was accused of embezzling about $80m (£42m) before he was forced from office in an army-backed revolt in 2001.

Estrada denounced the verdict as a "political move" and said he had been tried in a "kangaroo court".

Security was high in the capital Manila but fears that the verdict would spark mass protests appeared to be unfounded.

A few hundred pro-Estrada demonstrators had gathered for the verdict, but the protests were reported to be low-key and peaceful.

Appeal expected

Following a six-year trial, the special anti-corruption court ruled that Estrada was guilty of plunder.

He had been accused of receiving around four billion pesos ($85m) from illegal gambling, tax kickbacks and bribes while in power.

He was found not guilty of a separate charge of perjury. His son Jinggoy was acquitted of the charge of plunder.

Estrada was ordered to remain under house arrest on his country estate "until further orders". He is expected to appeal.

After hearing the verdict, the former president hugged his family and walked from court surrounded by family and well-wishers.

"This is the only forum where I could tell the Filipino people my innocence," he told reporters.

"That's why I took a gamble. I thought the rule of law will prevail over here. This is really a kangaroo court. This is a political decision."

Corruption allegations

A successful movie star with populist appeal, Joseph Estrada was elected president in 1998 by the biggest margin ever.

He was seen as a refreshing change from the wealthy elite that had previously dominated political life.

But it was not long before his presidency ran into trouble amid allegations of corruption.

He was accused of making crucial policy decisions with late-night drinking buddies at the presidential palace, and he admitted fathering a number of children by different mistresses.

One former gambling partner claimed he had delivered briefcases containing millions of dollars of cash bribes to the president's office.

He was ousted three years after coming to power in a revolt backed by the army and the church. His vice-president Gloria Arroyo took over.

His removal led to mass street protests in which four people died and more than 100 were arrested.

Mr Estrada has always denied the allegations, and accused Mrs Arroyo and church leaders of conspiring against him.

The government, clearly worried about the prospect of protests from Estrada's supporters in the wake of the verdict, made sure there was a high police presence around key buildings in Manila on Wednesday.

Mr Arroyo's spokesman Ignacio Bunye appealed for calm.

"We have a country to run, an economy to grow and a peace to win. We hope that this sad episode in our history will not permanently distract us from this goal," he told the Associated Press.