The prestigious BBC World Service, broadcasting radio news and commentary to 120 million people around the world, fell silent this morning for the first time in its 53-year history as British radio and television journalists began a 24-hour strike at midnight.

A statement, followed by music, was broadcast in English and was to be repeated on each of the World Service's 36 foreign-language news broadcasts throughout the day.

It explained that the strike had been called by BBC journalists "in protest against the decision by the BBC board of governors to withdraw a television documentary about extremism in Northern Ireland following a request by the British government."

Management employes of BBC 1, the state-owned corporation's television flagship, are due to read 10-minute headline bulletins at normally scheduled news broadcast times today. The remainder of the programs will be filled with entertainment. The 6 p.m. national news is being replaced by a rerun of "The Dukes of Hazzard."

BBC television workers began the call for the strike and were joined by BBC radio and most independent commercial television and radio workers throughout the country, resulting in a virtual blackout of all national and regional broadcast news in Britain.

The BBC board of governors and the corporation's editorial management team held separate and joint meetings yesterday in an unsuccessful attempt to avert the job action. Management proposals to run a revised version of the program, originally due for broadcast tonight, followed by a program of general discussion of media coverage of terrorism, were rejected by the board.

BBC sources confirmed widespread reports that the crisis could broaden with the mass resignation this week of senior management staff to protest what they see as board interference in their editorial prerogatives.

The crisis began 10 days ago, when Home Secretary Leon Brittan wrote the government-appointed board charging that the program was "against the national interest" and making an unprecedented public request for its cancellation.

The 45-minute documentary contrasts the lives of two Northern Ireland extremists, one a Protestant leader, the other Catholic.

Brittan and Prime Minister Margaret Thatcher particularly objected to interviews with Catholic leader Martin McGuinness, who is reputedly an official of the Irish Republican Army that advocates the use of violence to end British rule in Northern Ireland.

Although McGuinness is also an elected member of the Ulster National Assembly, the British-approved provincial legislature, Brittan said the program would "give succor to terrorism" practiced by the IRA.

In response to Brittan's request, the board -- which traditionally has left all editorial decisions to the management team -- took the equally unprecedented step on July 30 of screening the program and declared it unsuitable. It ordered the cancellation of the documentary, entitled "At the Edge of Union."

BBC television journalists then voted the 24-hour strike in protest against both the government -- which it charged with censorship -- and the board, which succumbed to government pressure, the journalists said. They charged that the state-owned corporation's reputation for independence from government interference had been damaged irreparably.

That theme has been picked up repeatedly by Soviet Bloc radio broadcasts in the past week. In its English-language service Monday, Radio Moscow said that the government and board actions proved that the BBC World Service, which has a wide audience in the Soviet Union, was a tool of the British government.

In a statement issued last night, board chairman Stuart Young defended the decision to cancel the program. He said the board originally decided to view the program in order to defend it better in refusing Brittan's request. After seeing it, however, the board decided it was "flawed" and guilty of "soft treatment" of terrorists.

Young blamed BBC management, which supported the broadcast, for failing to follow its own internal procedures in checking the documentary. The management has said it considered the program a balanced and useful contribution to national debate.

In a series of seemingly contradictory statements, Young said that the ban had nothing to do with the government and that it was a decision based on the board's own opinion of the program.

"This is not a whitewash," Young said. "The easiest whitewash would be to show the program . . . . This is people standing up for their convictions, . . . standing up for the editorial freedom of this country."

But Young also said that Brittan's overall request had "ominous overtones of censorship," with "greater implications" over and above the "flawed" documentary.

Referring to Brittan's letter to the board last week, Young said "every editor should read with care" one particular paragraph. In it, Brittan said that "even if the program and any surrounding material were as a whole to present terrorist organizations in a wholly unfavorable light, I would still ask you not to permit it to be broadcast."

Young said that he expected today's meeting with Brittan to be stormy. "I will indicate our independence by quite forcibly saying we will not accept censorship," he said.