Hosni Mubarak has returned to court in Cairo for the resumption of his trial on charges of ordering the killing of pro-democracy protesters and corruption, after the prosecution failed in an attempt to have the judges removed for bias.

The former Egyptian president was flown by helicopter to the court on Wednesday from a military hospital where he is being treated for a heart condition, and was carried into court on a stretcher, dressed in a black tracksuit and covered by a green blanket. As in thethe previous four hearings, he faced the court from a metal cage.

Mubarak is charged with conspiring in the killing of up to 840 civilian protesters during the 18-day uprising that brought about his fall after almost 30 years in power. He could face 15 years in jail or even the death penalty if found guilty.

He also faces corruption charges of using his position to enrich himself, his sons and a friend. Mubarak's sons, Alaa and Gamal, and an Egyptian businessman, Hussein Salem, also face corruption charges, while the former interior minister, Habib el-Adly, and six aides face conspiracy charges over the killing of protesters. All have denied the charges.

The trial was delayed when lawyers for the 840 people killed moved to have the presiding judge, Ahmed Refaat, and two other judges dismissed. They accused them of prejudice after television coverage of the trial was stopped and senior military leaders were allowed to testify in secret. The prosecution also claimed it was not allowed sufficient time to question the defence minister, Egypt's current ruler, Field Marshal Mohamed Hussein Tantawi.

Reports from the trial have suggested the prosecution is struggling to find proof that Mubarak personally ordered the killings or the diversion of state funds, as they have yet to persuade senior members of the regime to give evidence against him.

Lawyers warn the trial could continue for months or years because of the variety and complexity of the charges, and the number of witnesses.

The defence wants to examine the circumstances surrounding the killing of protesters after Mubarak's fall to support its argument that he was not responsible. His lawyers say unnamed third parties or "foreign hands" were behind the killings.

Rival groups of Mubarak supporters and opponents held demonstrations outside the court on Wednesday, separated by hundreds of police in riot gear. But there was no repeat of the violent clashes that had marred the earlier court sessions.

The trial of the ousted Egyptian president Hosni Mubarak, who is charged with the killing of protesters and abuse of power, has resumed following a delay of almost two months after lawyers demanded a new judge. Previous court sessions were marred by clashes between Mubarak supporters and Egyptians demanding the death penalty for their former leader outside the Cairo court, but there were no scuffles as Mubarak arrived on Wednesday