The government has asked the British Broadcasting Corp. not to air a television program on Northern Ireland on grounds that it gives "succor to terrorist organizations" and is "against the national interest."

Home Secretary Leon Brittan said that he "does not wish to exercise powers of censorship" but left open the possibility that he would use authority to do so granted to him in the license of the state-owned corporation.

Two weeks ago, Prime Minister Margaret Thatcher called on the media to adopt a "voluntary code of conduct" to starve terrorists of the "oxygen of publicity," and government officials today made clear that they consider the BBC program, scheduled to air in 10 days, a test of media good will.

The program, entitled "At the Edge of the Union," contains a lengthy interview with Martin McGuiness, an elected member of the Northern Ireland Assembly who also is believed to be chief of staff of the Irish Republican Army.

The BBC governing board scheduled an emergency meeting Tuesday to discuss how to respond to the request. BBC managers defended the program as "responsible and balanced" and said it had gone through mandated screening procedures for documentaries dealing with the sensitive Northern Ireland issue.

A decision to withdraw the program would be likely to cause extreme protest from reporters and producers, many of whom feel they have fought a constant battle against various British governments, in particular Thatcher's, to present what they consider fair coverage of Northern Ireland.

Although none would speak for attribution, one called it a "litmus test" of the government-appointed board's independence. "It is a very, very important case," he said. "The issues are clear-cut, and there's no possibility of fudging on it."

The program counterpoints McGuiness with Gregory Campbell, described as a "hard-line Loyalist," a member of the largely Protestant majority in Northern Ireland that favors British rule.

Controversy over the BBC broadcast began indirectly, during a press conference Thatcher held in Washington Friday. A reporter for The Sunday Times of London asked her if she would disapprove of a supposedly hypothetical program in which such an interview were featured.

Thatcher said she would "utterly condemn" it.

Once Thatcher found out that the "hypothetical" program was in fact on the BBC schedule, she ordered Brittan to investigate.

In a statement issued by the Home Office in his name today, Brittan said he "fully recognizes the freedom of the BBC in this matter; the government does not wish to exercise powers of censorship."

However, Brittan said he had "conveyed to the BBC in the strongest terms that . . . the program appeared to be giving succor to terrorist organizations by the opportunity for public advocacy of terrorist methods by the prominent member of the IRA . . . . It is contrary to the national interest that a program of the kind apparently envisaged should be broadcast" and Brittan "asked the BBC not to do so."

A Home Office spokesman said that neither Thatcher nor Brittan had seen the documentary.

The BBC is funded by a licensing fee charged all television owners. Although the BBC is operated under Royal Charter and theoretically immune from direct government interference, the government sets the level of the fee, and licensing legislation allows the Home secretary to "require the corporation to refrain" from broadcasting anything deemed inappropriate. That power, however, never has been used.