The guards were protecting the homes of two senior BBC executives Sunday as complaints from Christian groups at Saturday's showing of Jerry Springer: The Opera escalated into threats of violence.
The corporation employed a private security firm, Rubicon International, to safeguard the homes of the BBC2 controller, Roly Keating, and the director of television, Jana Bennett.
The pair were deluged with "threatening" and "abusive" phone calls; about 50,000 prior complaints about screening the musical were received by the corporation.
Keating took his family away for the weekend in what is believed to have been a pre-arranged move. The BBC said he would be back at his desk today.
The recently appointed controller of BBC2 and Bennett received a number of abusive calls after their numbers were printed on the Web site of a prayer group, Christian Voice, one of a number that have organized campaigns against the show. Threatening calls were also made to several BBC governors.
Before the broadcast the BBC had received a record number of complaints, mainly protesting that the show was blasphemous and obscene. The controversy helped the show to above-average ratings of 1.8 million at 10pm on Saturday night.
"We are pleased that a wider audience has been able to see this important piece of contemporary musical theater," said the BBC.
It has emerged that a large number of the complaints were by e-mail and used a similar form of words.
BBC insiders believe that the immediacy of e-mail, and the ease with which form letters can be sent automatically, dramatically boosted the number of protests. They expect the tactic's success to lead to similar orchestrated campaigns in the future.
But John Beyer, director of Mediawatch UK -- the broadcasting standards pressure group that also waged its own campaign -- said that the volume of protests indicated a wider dissatisfaction. "The fact is that the public have engaged in this debate about standards. People are very concerned about standards on television," he said.
The media regulator Ofcom has also received more than 7,000 complaints. The previous record was about Martin Scorsese's film The Last Temptation of Christ, which attracted 1,554 complaints to broadcasting watchdogs when it was shown in 1995.
By last night, the BBC had received 1,000 additional calls following the transmission of the program -- of these, 400 were made in praise of the decision to show the televised version of the West End musical.
Critics had claimed it featured 8,000 swear words. The show's co-writer, Stewart Lee, has said that in fact it contained fewer than 300 -- the higher figure is obtained by multiplying the offending words by the number of singers on stage.
The musical currently stars David Soul as the chat show host, and in its second half features Jesus in a sparkling nappy admitting to being "a bit gay" and a chorus line of dancing Ku Klux Klan members.
Christian Voice, which orchestrated its campaign from its Web site, organized a number of peaceful vigils outside BBC offices on Saturday night. Stephen Green, the national director of the group, yesterday admitted it had been "naive" to publish Keating's home number and said that it had been removed when BBC lawyers complained.
However, he vowed to press ahead with plans to pursue a private prosecution against the corporation for the common law offense of blasphemy.