Italian Prime Minister Silvio Berlusconi has gone back on trial on corruption charges after an immunity law was rejected earlier this year. The hearings in Milan resumed amid legal wrangling, as prosecutors accused the presiding judge of bias and called for his removal. Berlusconi allegedly tried to bribe judges to influence a business deal. The charges are the most serious Mr Berlusconi has faced in nearly 10 years of investigations. **Accusations of bias*** Prosecution lawyers requested that presiding judge Francesco Castellano step aside because of comments he made in a newspaper interview in 2002. Castellano was quoted by Il Giornale - owned by Berlusconi's brother - as saying the case against the prime minister was no longer justified. The lawyers said this indicated Mr Castellano was sympathetic to Berlusconi, but the panel of three judges rejected the claim. The panel is expected to take two months to wade through evidence collected over three years. Berlusconi's lawyer, Nicolo Gheddini, told the BBC he hoped the trial would be "wrapped up as soon as possible". "Seeing as the verdict will be positive, we're really not afraid," he said. **Immunity dropped*** Prosecutors allege Berlusconi, Italy's richest man, tried to scupper the takeover of state-owned food group SME by a rival firm in the 1980s, before he entered politics. The prime minister firmly denies any wrongdoing in the case and says left-wing magistrates are trying to undermine him. His trial was blocked in June last year after parliament passed government-backed legislation granting the prime minister and other top office holders immunity from prosecution. Critics accused the government of introducing the immunity bill to save Berlusconi from the embarrassing possibility of a conviction while Italy was chairing the presidency of the European Union. In January, the Constitutional Court ruled that the law violated Italy's constitution. A close associate of the premier, Cesare Previti, was cleared of charges of bribery, but received a five-year sentence for putting cash in the pocket of a Rome judge to maintain friendly relations. **Competing issues*** The re-start of the trial may add to the Berlusconi government's troubles. The verdict could fall at an inauspicious time - coinciding with European elections in June. Berlusconi's ruling centre-right coalition, already dogged by bitter infighting, has been further strained by the Parmalat scandal and a struggling economy. The premier now finds himself under attack for failing to deliver on election promises and for his continued support for the war in Iraq in face of anti-war domestic opinion. **PHOTO CAPTION*** Italian Prime Minister Silvio Berlusconi. (AFP)