Britons Riled Over Soldier’s Conviction : Ulster: Newspapers stir massive campaign against private’s life sentence in slaying of teen-agers.

LONDON â€”  In just a few days, the plight of a private in the British army, convicted of murder, has become a cause celebre here .

Britain’s national newspapers have taken up his cause, mounting a massive letter-writing campaign on his behalf. Veterans have warned they might not observe V-E Day celebrations this year in protest. Prime Minister John Major has indicated a “close interest� in the case. And Prince Charles, colonel in chief of the soldier’s Parachute Regiment, is said to be kept fully informed of developments.

All the attention is focusing on Pvt. Lee Clegg, who was assigned to a parachute battalion in Northern Ireland 4 1/2 years ago when he was 23. The concern surfaced when the Law Lords, Britain’s equivalent of the U.S. Supreme Court, earlier this month rejected his appeal of his murder conviction and life sentence.

On Sept. 30, 1990, Clegg was a member of a group of soldiers manning roadblocks in West Belfast--a mission, he thought, to stop Irish Republican Army terrorists.

That evening, a stolen car sped toward the checkpoint and did not stop. Several soldiers opened fire at the car, killing the driver, Martin Peake, 17, and his passenger, Karen Reilly, 18. The dead teen-agers turned out to be joy riders--and it was never determined why they did not halt when ordered to.

Clegg operated under rules of engagement that let soldiers open fire if they thought their lives were endangered. A preliminary investigation seemed to exonerate him of serious wrongdoing. But a later investigation recommended that Clegg face trial.

He went before a Belfast magistrate and was judged to have fired three shots legally at the car as it came toward and past him. But his fourth bullet hit the car as it was passing and killed Reilly; his firing was deemed wrong because officials said the danger to Clegg had passed.

In ordinary circumstances in Britain--and in America--the most serious charge against Clegg would have been manslaughter. But in Northern Ireland, a soldier who kills a civilian without legal justification must be convicted of murder--with a mandatory life sentence.

The judge found Clegg guilty of firing the fourth, fatal shot and sentenced him to life imprisonment. He has been in prison ever since, while his appeal moved through the courts.

This month, the highest court ruled that a soldier who kills while using excessive force in self-defense is guilty of murder, not manslaughter. But the judges did express concern about the legal definitions of murder in Clegg’s case, as well as his mandatory life sentence.

Legal support to free Clegg is based on the argument that he is a victim of a gross miscarriage of justice. His conviction indicates, it is widely claimed through letters to the national press, that British law “is an ass.� Further, a wave of protest among senior officers has suggested that morale in the armed forces has been shaken by Clegg’s conviction; military officials say the private was merely following orders in a difficult, confused situation.

The case has taken on political overtones: IRA sympathizers claim that if Clegg is freed, it would indicate that justice favors army soldiers over republican civilians.

But Clegg’s many supporters in and out of the army and government stress that rules of engagement place a severe burden on young soldiers who have a split second to decide whether to shoot in dangerous circumstances. They find it inexplicable that a private should be singled out for life imprisonment--rather than blame being placed on others higher in command who failed to give clarifying orders.

Some argue that Clegg provides a convenient scapegoat--and that it would be hard to free him without angering Irish republicans at a sensitive time in the Northern Ireland peace process.

Still, aroused British public opinion is running heavily in favor of an early release for Clegg. And members of Parliament have called for a review of the case.

Through it all, Clegg maintains his innocence and says all he wants is to return to his unit.

“The irony is,� he told the Daily Telegraph, “if war broke out tomorrow, I would have been willing to lay down my life for these pillars of society who have sent me to prison for life.�