The estate of Spirit guitarist Randy California raised a lawsuit two years ago, stating that the band's 1967 instrumental Taurus was the source of the opening sequence from Zeppelin's 1971 classic.

California had said in interviews before his 1997 death that he had no doubt his work had been copied. But Page last year dismissed the suggestion as "ridiculous," and in February declared that he'd never listened to Taurus until confronted with the lawsuit.

Michael Skidmore, representing California's estate, said that Page could have heard the piece while the two bands toured the US together in 1968 and 1969.

Led Zeppelin's legal defense has not been based on the alleged similarity between songs, but on whether the Spirit party have any right to act over the matter. It's argued that California wrote Taurus under a contract that surrendered all rights to his work, and that he dismissed any claim in a 1991 interview in which he said: "I'll let them have the beginning of Taurus for their song without a lawsuit."