LOS ANGELES (Reuters) - A federal judge has ordered the FBI to turn over files on John Lennon to a California professor who said the documents show Britain's domestic spy agency shadowed the late Beatle's political activities.

Rejecting the U.S. government's national security claims, U.S. District Judge Robert Takasugi on Tuesday brought to a close a 23-year battle waged by Jonathan Wiener, a University of California professor who requested the information for a book he was writing shortly after Lennon was murdered in 1980.

"The issue has become government secrecy and the absurdity that, today, when the FBI should have better things to do they are still trying to keep secret 34-year-old documents about the anti-war activities of a dead rock star," Wiener said.

The documents revealed efforts by President Richard Nixon to deport Lennon to silence his anti-war activities in 1971 and 1972, Wiener said.