Malaysia's sacked finance minister, Mr Anwar Ibrahim, has asked the judge in his trial on charges of corruption to step down from the case, saying he has not been given a fair trial.
Counsel Mr Raja Aziz Addruse filed the motion on Monday with the High Court in Kuala Lumpur and it was supported by an affidavit from Mr Anwar.
The documents were the latest surprise twist in the 41/2-month trial that has exposed divisions in Mr Mahathir Mohamad's ruling party and stirred political turbulence.
The motion says that Judge Augustine Paul "ought not to continue to hear and try the issues and matters in the trial", or alternatively "be required to discharge himself".
A lawyer representing Mr Anwar said that under court procedure, Judge Augustine himself would normally take up the motion.
In his affidavit, Mr Anwar said he had "grave apprehension that the learned judge might not bring an impartial and unprejudiced mind with respect to the issues and matters before him".
He added: "I do not believe I have been given a fair trial."
The Prime Minister, Mr Mahathir, sacked Mr Anwar in September after their differences over the economy and politics reached breaking point. Mr Anwar was later arrested after leading 30,000 anti-government protesters through the capital calling for an end to Mr Mahathir's 17-year rule.
He has pleaded not guilty to five counts each of corruption and sodomy, arguing he was the victim of a conspiracy by high-level associates of Mr Mahathir to end his political career.
Judge Augustine, who was promoted to the High Court bench last May, has ruled that the political conspiracy argument is irrelevant.
In January, he threw out months of evidence relating to allegations of sexual misconduct by Mr Anwar.
Lawyers acting for Mr Anwar protested that the ruling deprived them of an opportunity to disprove the accusations and clear their client's name.
Judge Augustine also accepted the prosecution's amendments to the four corruption charges under examination since November, which had the effect of reducing the government's burden of proof.
Mr Anwar's 16-page affidavit summarised his views of the judge's critical rulings over the course of the trial.
The defence closed its case and is to begin summarising on March 23rd. Defence lawyers expect the judge to deliver a verdict in early April, and say they doubt the prosecution will press the remaining six charges.
Mr Anwar's wife, Wan Azizah Wan Ismail, asked at a news conference why the motion had been filed, said: "We're just trying to get justice here."
Mr Anwar said the judge had "clearly made a prejudgement on the issues, precluded my counsel from presenting my case in full, has expunged evidence favourable to me (and) had applied between the prosecution and the defence different standards with respect to the admissibility of evidence."
On Monday, Judge Augustine barred the defence from calling 10 new witnesses. Asked if that move had prompted the motion, Ms Wan Azizah said: "That was part of it."