A federal appeals court delivered an unusually blunt rebuke yesterday to Northern Virginia's controversial U.S. District Judge Oren R. Lewis, saying the judge's 250 interruptions of a "routine" one-day trial prevented two Kentucky men from receiving a fair trial.

A three-judge panel of the 6th U.S. Circuit Court of Appeals ruled unanimously that Lewis' behavior during a 1977 Louisville trial was "not impartial" and that the 76-year-old senior judge had acted like a "surrogate prosecutor" during the proceedings.

In an 11-page opinion, the judges overturned the convictions of Darry 1 Gordon Hickman and Fred McArthur Head and ordered new trials for the men on weapon-possession charges.

In pointed language, the three-judge panel said Lewis had "frustrated the defense at every turn and infringed upon" the defendants' right of cross-examination by his constant interruptions. "The only impression which could have been left in the mind of the jury was that the trial judge was a surrogate prosecutor," the court said.

Lewis, a former newspaper executive who was named to the federal bench 19 years ago by President Dwight D. Eisenhower, declined to comment yesterday on the opinion. "I've never commented on any case I've been on yet and I won't now," he said in a telephone interview. "It's just not proper in my opinion."

In Alexandria, where he sits in a District Court, Lewis is well known for his cantankerous and often outspoken style. The appeals court opinion, released in Cincinnati yesterday, was not the first reprimand Lewis has received from an appeals court for his conduct of a trial, but some lawyers described the latest opinion as one of the most outspoken they had ever seen on a federal judge's behavior.

Although Lewis is considered semiretired, he regularly hears cases in Northern Virginia, and most recetly presided over the celebrated lawsuit that the Central Intelligence Agency brought against former CIA employee Frank Snepp. At the Snepp trial Lewis' noisy expressions of antipathy toward Snepp and his lawyers astounded many in the courtroom.

Lewis was sent to Louisville in the fall of 1977 to help that area with its crowded court decket. But the appeals court found his behavior in the trial of the two Louisville men dangerously biased.

The appeals court panel said that Lewis' examination of one witness was "brilliant," but it added that the questioning "would have been entirely proper had it been done by the prosecutor."

The appeals court found other faults:

"When one combines the limitation on cross-examination, the antidefendant tone of the trial judge's interruptions, the wholesale taking over of cross-examination of defense witnesses by the trial judge; one is left with the strong impression that these two defendants did not receive the fair and impartial trial which the Sixth Amendment to the Constitution guarantees them.

"We are convinced that, judged as a whole, the conduct of the trial judge must have left the jury with a strong impression of the judge's belief of the defendants' probable guilt such that it was unable to freely perform its function of independent fact finder."

Lewis, a former circulation manager with the now-defunct Washington Times-Herald and an executive for the Hearst Newspapers, was appointed to the federal bench after practicing law in Northern Virginia for 21 years. He is a 1939 graduate of the former National Law School, now the George Washington University Law School.

Lewis is known to cut off witnesses and lawyers with frequent objections to their remarks and to often castigate lawyers from the bench in stern language -- points that the Cincinnati court raised in its opinion yesterday. While some Virginia lawyers speak of Lewis in terms of amusement, young lawyers often express fear of going before the judge.

His reversals in Virginia have sometimes resulted from his style of attempting to rapidly move through cases. In 1972, the 4th U.S. Circuit Court of Appeals overturned a murder conviction from Lewis' court, saying the judge erred by refusing to allow more than one character witness to testify for the defendant.

In 1968, his conviction of a Vietnam war protester was also overturned by an appeals court, which cited his comments about a Harvard University graduate. "People who are as educated as he and do things like this ought to pay the bill," Lewis had said in handling the protester a 30-day jail sentence.