The Cosby Show veteran is facing trial for three charges of felony indecent assault amid allegations he drugged and sexually assaulted former Temple University employee Andrea Constand at his Pennsylvania home in 2004.

He was not charged at the time of the incident and maintains his innocence, but he faced questioning in 2005 and 2006 as part of Constand's civil suit, which was subsequently settled out of court.

The criminal case was reopened last year (15) after the star's sealed deposition was made public, revealing Cosby had enjoyed a number of extramarital affairs and confessed to buying sedatives to give to women he wanted to sleep with.

The actor's attorneys have repeatedly argued against allowing the deposition to be used against him in criminal court, claiming Cosby only agreed to testify after a previous District Attorney promised not to prosecute him over the 2004 incident.

The now-79-year-old never obtained a formal agreement with the D.A. in question and instead tried to have the evidence sealed again, but on Monday (05Dec16), Montgomery County Judge Steven O'Neill ruled in favour of the prosecution.

"This court concludes that there was neither an agreement nor a promise not to prosecute, only an exercise of prosecutorial discretion," the judge wrote.

The court official is also set to rule on how many of Cosby's other sex accusers will be allowed to testify against him to help prosecutors establish a pattern of behaviour. Hearings for those arguments are set to take place next week (begs12Dec16).

Cosby's attorneys are fighting the motion, insisting the actor's failing eyesight, coupled with a memory which has "substantially declined", means he is unable to positively identify his accusers and is therefore unable to mount a substantial defence.

More than 50 women have come forward with decades-old allegations of inappropriate behaviour, drugging and/or rape against Cosby in the past two years. The actor's representatives have repeatedly denied the accusations.