London — Col. Muammar Qaddafi's code of violence has brought relations between Britain and Libya to a state of crisis. After more than four years of sporadic outrages, including assassinations and bombings in British cities, Libyan revolutionaries in London found themselves Tuesday at the center of a vast police siege of their country's ''people's bureau'' (i.e., embassy).
Earlier, during anti-Qaddafi demonstrations, a London policewoman was shot and killed by a person inside the embassy building. Ten other people, all thought to be Libyans, were injured in a hail of machine-gun fire, apparently directed by an official of the diplomatic mission from a first-floor window.
The troubles seem to arise from tensions between Libyans in Britain who are loyal to Colonel Qaddafi and Libyan students opposed to his regime. In the last two years anti-Qaddafi student activity in Western Europe has become better organized, and British police believe this has angered the Libyan leader.
Relations between Libya and Britain began to deteriorate after Colonel Qaddafi declared in 1979 that in the future, his country's embassy in London would be run by a revolutionary committee. Similar actions were taken in other world capitals, including Washington.
Soon afterward, two Libyan nationals were assassinated in London, and this led to the expulsions of two of Colonel Qaddafi's diplomats.
In February Libyan revolutionary students in London announced they had staged a takeover of the people's bureau. Qaddafi was believed to have supported the move. A few days later, bomb attacks on news agents and a restaurant injured 24 people. This led to the deportation from Britain of five Libyans.
But Britain agreed to let the people's bureau continue to operate, despite police concern that it was the center for illegal terrorist activities in Britain and elsewhere in Europe. Libya was warned that diplomatic immunity must not be exploited in the pursuit of violence.
Qaddafi has refused, nonetheless, to curb the activities of his revolutionary supporters. London police sources speculated that the recent shooting incident at the people's bureau was an attack by a pro-Qaddafi official on anti-Qaddafi demonstrators outside the building.
In the early stages of the crisis Tuesday, the British government moved with great caution. The embassy building enjoys diplomatic protection, meaning police cannot enter without official Libyan permission. And there are more than 8,000 Britons living in Libya, and British officials were acting in the knowledge that Qaddafi could make conditions for them extremely difficult.
Police quickly closed in on the 18th-century building, sealing off all exits from St. James's Square, site of the Libyan diplomatic mission in the heart of the West End.
Urgent talks at high government levels were directed at ways of ending what rapidly developed into a siege as Libyan officials inside the people's bureau refused to give themselves up. Only one Libyan official emerged during the day, but police thought he was not the person who had fired the machine gun.
Diplomatic observers could not recall an occasion when an embassy building in London had been besieged by police. The nearest British parallel was the seizure by Iranian revolutionaries of hostages in Iran's London embassy in May 1980. The embassy was later stormed by Special Air Service troops.
Four years ago a group of Libyan diplomatic officials being expelled from the United States left their Washington embassy only after a siege of the building by the FBI.