Britain's Defense Ministry has approved the outlines of a new system of media control designed to "protect military information" during times of conflict while avoiding the kind of censorship charges that arose during the 1982 Falklands War with Argentina.

In a ministry "white paper" issued late yesterday, the government rejected as not "practicable today" recommendations by a ministry-sponsored study group that it establish a formal World War II-type press censorship mechanism that would go into effect during a major conventional war.

But in proposals that go far beyond those adopted by the Pentagon last year to cover similar circumstances, the ministry accepted a recommended "bargain" with the media -- to apply to both limited and general war -- under which war-front correspondents would agree in writing, in advance, not to report anything the military did not want them to report.

In exchange, the journalists would be made, in effect, part of the military unit or operation they were covering. They would be provided with uniforms, transportation with the troops, briefings and assistance in transmitting their dispatches.

At home, a government "advisory group" would counsel editors and journalists on coverage. The assumption, a defense official said today, is that "the British media would be fundamentally on the side of the government and the side of the armed services. The media would reflect that approach and be prepared to be advised on what they should or shouldn't say."

If the media decide not to heed the advice, the official said, the "guidance" system would be "underpinned by the government being able to call up statutory remedies if necessary," including Britain's severe secrecy and national security regulations.

Those regulations, and the way in which the British government managed press coverage of the Falklands crisis, have been the object of some envy within the Reagan administration, which ran into its own media relations problems because of the way it restricted press access during its 1983 invasion of Grenada. But media outrage, congressional pressure and First Amendment tradition have made it difficult for the administration to effect any widespread institutional changes in the way the U.S. press does business or sees its mission.

The tradition here is quite different, and press reaction to the proposals, which the government said will be discussed with the media before implementation, was subdued. While antisecrecy activists denounced the report, many journalists and editors pronounced it "business as usual" and most newspapers did not cover its release.

When asked, reporters and editors acknowledged that the British media, particularly on defense issues, traditionally have not considered themselves adversaries of the government.

"There's a tradition here of the background briefing without attribution, of voluntary censorship, the 'old boy' network" between officials and the journalists who cover them, said the defense correspondent of a major daily. Based on the experiences of World War II, there was general acceptance that the government had the right, as well as the power, to control the dissemination of military information.

It was not until the Falklands, a limited conflict in which the British government lacked a monopoly on information and was accused of slanting or withholding some of what it did have and of severely restricting access to the war zone and communications out of it, that journalists here began to rebel.

"Britain actually woke up to the fact that the press was not going to be a toady," the defense correspondent said.

But journalists and government officials alike said today that the new system will serve primarily to institutionalize the existing system of de facto government control. "We effectively had control during the Falklands," the defense official said. "This puts it on an organized basis, where everyone knows the limitations and expectations in advance" and has no cause for complaint afterward.

"I don't think it has any great practical effects on anybody," said David Walker, news editor of the Financial Times. One of the biggest problems his paper faced during the Falklands War, Walker said, was when "we found ourselves on the receiving end of conflicting reports -- out of Washington and Buenos Aires -- and tried to get confirmation of something here and couldn't."

The new system "assumes that only the person on the spot is covering the story," Walker said. "With these conflicting accounts, more harm than good is done by the authorities."

The white paper, he said, "takes for granted that the reporter is on one side or the other. It takes for granted that the wish not to put people's lives at risk is the same as the wish to provide the point of view of the government of the day. And they're not."

While the impetus for the new proposals clearly stems from the limited nature of the Falklands engagement, the system also is intended to cover Britain's participation in major European and worldwide conflicts, and officials said it will be presented for consideration by the NATO allies in the coming weeks.

"The report is very careful to point out that it is no good Britain doing it on its own," the defense official said. "There are 15 other allies," he said, whose journalists, in the event of a major conventional war, could be filing "unbargained" reports far beyond what the British press had agreed to.