By Danny Wood
BBC News, Madrid
The trial of 30 suspected Islamic militants accused of planning a series of bomb attacks on Madrid has started in Spain's High Court.
Mohamed Achraf is accused of plotting court bombings from prison
The alleged plot was uncovered months after the March 2004 train bombings in the capital, which killed 200 people.
The group are on trial in the same court they allegedly aimed to destroy. They have denied the charges.
Prosecutors say they planned to drive a truck packed with 500kg (1100lb) of explosives into Spain's High Court.
The idea was to kill hundreds of staff and destroy evidence connected with anti-terrorist trials, including the March 2004 Madrid train bombings, prosecutors allege.
According to the Spanish authorities, the group's other targets included a major train station and the headquarters of the conservative Popular Party.
Plotted from prison
The charges against the men, most of whom are Algerian and Moroccan, include conspiracy to commit murder and membership of an armed group. The key suspects could face prison terms of at least 10 years.
Prosecutors say the group's leader, Mohamed Achraf - also known by the alias Abderrahman Tahiri - plotted the attacks from his prison cell.
The alleged plot involved driving a truck bomb into Madrid's High Court
He is accused of organising terrorist cells known as the Martyrs of Morocco to carry out his schemes.
The trial's start comes two weeks before sentences are announced in one of the biggest terrorist trials in Spanish history.
The men accused of involvement in the March 2004 Madrid train bombings are due to appear in court on the 31 October to hear the judges' verdict.