Patrick Magee, 35, of Northern Ireland was found guilty of murder today for the 1984 bombing of a Brighton hotel in which most of the British government's most senior officials were staying. Prime Minister Margaret Thatcher and her Cabinet narrowly escaped death in the explosion, which killed five persons and injured 33 others.

After five weeks of testimony, the six-man, six-woman jury took five hours to reach its unanimous verdict against Magee. Deliberations will continue Wednesday on separate charges that Magee and four others, all described as members of the outlawed Irish Republican Army, plotted a separate campaign of hotel bombings to take place at British resorts last summer.

The alleged conspiracy was aborted when police arrested Magee and the others last June in Glasgow.

The Brighton bombing took place at the Grand Hotel in the early morning hours of Oct. 12, 1984. The Conservative Party conference was being held in the city, and most senior government members were staying at the hotel. Although the IRA, which is fighting to end British rule in Northern Ireland, has been held responsible for numerous bombs in mainland Britain that have killed 82 persons since 1972, the Brighton attack was by far the most significant politically.

An IRA communique after the explosion said, "Today we were unlucky, but remember we only have to be lucky once."

During the trial, prosecutor Roy Amlot said the time-delayed bomb, placed in room 629 of the hotel by Magee, had "come within an inch" of wiping out the British government. Amlot called it "one of the worst acts of terrorism ever in Britain."

Among the five persons killed were one member of Parliament, and the wife of another. Norman Tebbit, who now serves as Conservative Party chairman, was severely injured, and his wife was left paralyzed.

At the time of the bombing, the head of Britain's antiterrorist police said that it was "calculated to kill, injure, maim, disfigure and disable as many people as possible, including Mrs. Thatcher and the Cabinet."

The bathroom in which the bomb went off was directly next to the room in which Thatcher at the time was working on her conference speech.

In the aftermath of the bomb, Thatcher received high praise for her coolness and composure. Barely 12 hours after the explosion, she delivered her speech.

Her narrow escape is believed to have stiffened her resolve to fight against terrorism, including her ready agreement to assist the United States in its military attack against Libya last April. The Brighton bombing also brought significantly increased security for British government officials. Anyone entering hotels housing officials, or the conference center, during last year's Conservative conference, held in Blackpool, was subjected to a body frisk and metal detectors.

Magee, who pleaded not guilty, presented no witnesses in his defense and did not testify during the trial.

According to the prosecution, police had begun hunting Belfast-born Magee as a suspect within three months after the explosion, based on identification of his fingerprints obtained from a hotel registration card.

He was captured when Scottish police last June raided an alleged IRA hideout in Glasgow. There, they allegedly also found evidence indicating that Magee and four others arrested with him were planning a 16-bomb campaign during last summer. The bombs allegedly were to go off at hotels, four in London and the rest in coastal towns.

The prosecution in the Brighton case said that Magee had registered at the hotel under a false name a month before the conference, and had concealed a 20- to 30-pound explosive device under the bathroom floor in room 629. The timer, the prosecution said, was set to explode 24 days, six hours and 35 minutes later, when the guests were asleep at 2:54 a.m. on Oct. 12. Magee's lawyer, Richard Ferguson, claimed during the trial that the police planted his print on the card to frame him to restore their credibility after the Brighton explosion. Defense counsel suggested that Magee was singled out by police because "his face fit," and because he was a known IRA activist.

In his instructions to the jury, Judge Leslie Boreham warned that "it has been suggested that you might be induced, through emotion, simply to find a scapegoat for the Brighton affair." To do so, Boreham said, "would be more enormous than the crime that was committed at Brighton itself."

The jurors were instructed to take a "quiet, clear look" at the evidence. "You are left with one question only," Boreham said. "Was it Magee?"

Before being taken from the Old Bailey today in a sealed police van under heavy guard, Magee turned to the public gallery and shouted "good luck," apparently to his wife.