U.S. District J. Robert Gary Klausner, who is presiding over a trial which will decide whether the rock group's hit Stairway To Heaven was plagiarised from Taurus, a 1967 instrumental by the band Spirit, ruled certain evidence about the rock group's past could not be heard in court.

Jury members will not hear testimony relating to bandmembers' alleged drug use or previous accusations of plagiarism.

According to The Hollywood Reporter references to the personal wealth of bandmembers Robert Plant and Jimmy Page, who are currently credited as the song's writers, are also banned from the Los Angeles trial.

The ongoing lawsuit against the rock legends was brought by Michael Skidmore, a trustee for the late Randy Wolfe, also known as Randy California, who was Spirit’s guitarist and the composer of Taurus.

Skidmore claims Page was inspired to write the song after hearing Wolfe's composition while touring with him in the late 1960s.

At a hearing earlier this month (Apr16) the defendants claimed the chord progression used in Taurus is so common it does not deserve copyright protection.

However Judge Klausner ruled that the case could proceed to trial, calling the similarity to the two songs "substantial".

The trial is scheduled for 10 May (16).