The California Supreme Court has decided to overturn 1975 law that requires prison terms for persons who use a gun during a violent crime, but has not made the decision public, well placed court sources have revealed.

The decision is certain to anger law enforcement officials around the state.

The court sources said Monday that the decision was reached on a 4 3 vote, with Chief Justice Rose Elizabeth Bird, whose name goes before voters Tuesday, among the majority.

The sources said that announcement of the decision is being delayed by Associate Justice Mathew O. Tobringer, who has been one of Bird's strong supporters against a well organized campaign to win voter disapproval of her appointment to the court.

When asked whether he was delaying the decision, Tobriner replied: "I'm utterly sealed. My oath is not to disclose anything that goes on in this court. I can say nothing, absolutely zero,zero, zero.

However, two other justices confirmed that individual decisions were signed some time ago by all members of the court. The justices could not explain why the outcome has not been announced.

Bird could not be reached for comment.

Nearly a month ago, Atty. Gen. Evelle J. Younger, the Republican candidate for governor, suggested that some potentially controversial court decisions were being withheld because of their possible effect on the election. A spokesman for Bird denied Younger's claim.

The 1975 law in question is the keystone of an advertising campaign sponsored by law enforcement that has made the slogan, "Use a gun, go to prison," well-known around California.

Gov. Edmund G. Brown Jr. has frequently cited the statute as one of the law enforcement accomplishments of his administration, in effect, the measure denies a judge the right to grant probation after a defendant has been convicted of using a gun while committing a violent crime such as murder, rape or robbery.

The Supreme Court decision upholds a San Mateo County Superior Court judge who placed convicted robber Harold E. Tanner on probation after ruling that the 1975 law unconstitutionally limited judicial discretion.

Assistant Attorney General Michael V. Franchetti, a legislative representative for the state Department of Justice, predicted that law enforcement officials will "rise up in anger at the decision."

"This is really an important law, more than the death penalty," he said, "This is really working; people are going to prison. The death penalty is just sitting around."

Franchetti said that law enforcement officials probably would attempt to nullify the court decision during the next session of the legislature, which begins Dec. 4.