THE British response to the shooting incident at the Libyan People's Bureau in London on April 17 was measured and realistic. An American response - had a similar thing happened in Washington - would undoubtedly have been less measured. The contrast illustrates something of the difference between the environment for diplomacy in the two countries.
The British felt they were limited in their response to the event. If they had any chance of capturing the gunman, it would only have been by a forced entry into the Libyan bureau. Even that would not have guaranteed that the right person would have been identified. A forced entry, despite the anomalous nature of the People's Bureau, would have violated diplomatic immunity; the British, with an eye to the protection of their own embassies abroad, saw grave disadvantages in that step.
l. The British negotiated: There is an almost automatic assumption in Britain that, where an incident of this kind occurs and where there is feasible contact between the parties, negotiations must be tried. In the United States, negotiation, particularly with ''terrorists,'' is suspect. Television photos of an American ambassador, under such circumstances, sitting and talking with a Libyan official would have provoked serious criticism of the policy. A public debate over the wisdom of negotiating would have made the discussions - and a solution - more difficult.
2. The British confined the issue to the incident: Comment in Britain from official circles and, presumably, the subject of the negotiations themselves were limited to how to resolve the question of finding the gunman and the arms within the People's Bureau. In the US, both official and public comment would have widened the issue to include national pride or humiliation, the test of wills, ''international terrorism'' and the full range of charges against Muammar Qaddafi and his regime.
3. The British limited comments to a nonpolitical level: As of this writing, Prime Minister Margaret Thatcher has made no comment and appears to be under no pressure to do so. Official statements have been limited to those directly involved - the home secretary, the police, and the British ambassador in Tripoli. They are measured, brief, and nonpolemic. In the political world of the United States, it would be almost impossible for a president or a secretary of state to avoid pressures for statements or answers to questions that would inject a broader, rhetorical element into the picture. ''We will not be pushed around by a dictator,'' ''Terrorism will not go unpunished,'' ''America must show it has the will to curb such acts of international outlawry.''
4. Britain has made no military moves: Nothing reported in the US so far suggests that the British considered any sort of military pressure against the Libyans. Demands in the US would come almost immediately from the Congress, the public, and within an administration. At a minimum, some officials would leak information about fleet movements to suggest the US was ready to apply such pressure.
5. The British community remains in Libya: There has been little talk in Britain of encouraging British subjects to leave Libya or talk of a mass hostage situation. In the US, the opposite would be true. Even if citizens were not immediately evacuated - if that were possible - every effort would be made to get them to leave later.
The British have handled the matter quite differently than we probably would in this country. They and a world concerned with terrorism might have wished for a different outcome. On the other hand, they have made their point and have, with the Libyans gone, removed a terrorist center from London. They have, as well, avoided those polemical exchanges with Qaddafi that might have made the position of the British community - and the remaining Americans - more precarious. Given the circumstances, it is hard to see how any more could have been achieved by a different, ''tougher'' style of diplomacy.