-Britain's press won a major victory here last week when the government abandoned its "spy" charges against two reporters and an intelligence corporal they had interviewed for a story.

The three, however, are still on trial. They face two-year sentences for allegedly violating another section of the Official Secrets Act, which the government had pledged it would never again invoke.

But the suppression of the more serious counts is regarded as a landmark for a free press. Even if the government succeeds with its prosecution of the lesser charges, it will further discredit the highly controversial official secrets law.

It is now seeking to convict the three under a catchall section of the law that prohibits giving or receiving any unpublished official information. This clause is so sweeping that theoratically it could jail for two years a civil servant who gave and a reporter who received an unpublished survey of government tea-drinking habits.

The three men on trial at the historic Old Bailey are Duncan Camphell, 25, a writer for the socialist weekly New Statesman, Crispin Autrey, 32, of Time Out, a leftist entertainment guide, and John Berry, 34, a social worker who once served in Britain's National Security Agency.

Nearly two years ago, Campbell, a specialist at exposing the government's electronic spying, and Aubrey interviewed Berry at his apartment. All three were promptly seized and arrested before a word had appeared in print.

To the surprise of many legal observers the government accused them of breaching an Official Secrets Act clause that had been designed for real spies. It provides a 14-year sentence for giving or receiving data to help an enemy.

The prosecution conceded that Campbell, Aubrey and Berry had no intention of aiding an enemy and were simply collaborating on an article. Nevertheless, until this week the three were charged under the espionage section.

Their first trial collapsed in September when the defense belatedly discovered that the foreman of the jury looked suspiciously like a government plant. The man, a former paratrooper in a military spy-commando unit, had been lobbying his fellow juniors for convictions before the defense had even begun its case.

The second trial lasted 15 days before the government gave up on its spy charges. Lawyers for the defense ridiculed the government's case, showing that the "secrets" Berry had told to Campbell and Aubrey had all been published, even in military house organs.

At one point, Col. Hugh Johnstone, a prosecution witness and former chief of the army's Signals Intelligence, complained from the stand that the published material cited by the defense was itself a violation of the Official Secrets Act. The "offender" here was a journal called The Wire, published by the Royal Corps of Signals Association, veterans of the colonel's outfit.

At preliminary hearings, the colonel had tried to hide his own identity and appear simply as "Col. B." But members of Parliament and newspapers device to prejudice the atmosphere surrounding the defendants and limit their ability to cross-examine.

On another occasion, a major who had been the "security officer" at a Cyprus base for Signals Intelligence testified that the role of the installation was also an official secret. The defense showed that the base, which monitors foreign military radios, had been described earler not only in The Wire but also the official proceedings of the House of Commons and general newspapers.

The government finally conceded that whatever Berry-who left the army eight years ago-told the pair could not aid an enemy. So the "spy" section charges were dropped, although prosecution continues.

The section of the law now being used, has been something of an embarrassment since it was adopted in 1911. So, two years ago, Merlyn Rees, the home secretary, promised the House of Commons:

"The government . . . (accepts) that the mere receipt of official information should no longer be an offense."

The belief here is that overzealous spy catchers in Rees' department grabbed Campbell, Aubrey and Berry without telling their boss. So the bureaucracy is making mincemeat of the home secretary's pledge.

Commons is not in session now so no members can protest the continued prosecution. Newspapers here cannot comment on a pending case. That would be contempt and land their editors in jail.

The trio continues to stand in the dock, a fenced-off area for criminal defendants in the middle of the Old Bailey court. But whether their case-frequently heard in secret-will ever reach the second jury is still a question.

The overager lobbyist who served as foreman of the first jury was discharged, along with his colleagues.

Under American law, he could face contempt charges for his conduct. But they do things differently here. The government is now considering whether to punish for contempt still another new statesman journalist: the writer who exposed the foreman's role.