Christians angered by the Jerry Springer musical broadcast by the BBC are to pursue a private prosecution against the corporation for alleged blasphemy.

Critics were angered by the show, shown uncut on BBC2 on Saturday night, because of foul language and scenes showing Jesus in a nappy admitting he is "a bit gay".

As the row escalated, senior BBC executives were given security guards after phone threats were made by irate campaigners.

Their private phone numbers were posted on a website and the matter has been reported to the police.

It is believed Roly Keating, the controller of BBC2, and Jana Bennett, the director of television, are among those who have been given protection.

Stephen Green, national director of Christian Voice, a UK-wide prayer group, said: "We will probably bring a private prosecution against them for the common law offence of blasphemy. Having seen the thing, if this is not blasphemy, nothing is."

He added: "There will be nothing sacred if we cannot successfully prosecute the BBC."

Mr Green plans to take legal advice early next week.

Reacting to news that threats were made against BBC executives, he said: "We completely distance ourselves from it and condemn these threats."

The vice-president of the National Secular Society, Terry Sanderson, said: "It is time for the authorities to call a halt to these threats and menaces against innocent people and their property.

"Unless these extremists are stopped now, there is the distinct possibility that someone is going to get hurt."

The BBC said there were less than 300 offensive words in the opera, even under the broadest definition of the term, including 117 "f-words" and seven "c-words".

Overnight viewing figures indicate Jerry Springer - The Opera, starring David Soul, had an average audience of 1.8 million viewers.

A BBC statement said: "We are pleased that a wider audience has been able to see this important piece of contemporary musical theatre."

Since the programme went out, 317 calls had been received from viewers.

Figures showed 28 per cent appreciated the show, 16 per cent were happy it was broadcast, 33 per cent thought it was offensive and 23 per cent though it should not have been broadcast.

Before the show went out, the BBC received 47,000 calls and letters over the issue, the majority of which were negative.

Demonstrations were held outside BBC offices across the country on Saturday night.

Lobby group Mediawatch-UK claims the show breached corporation's guidelines.

John Beyer, director of Mediawatch-UK, said: "The whole show was very offensive. Some of the imagery was more offensive than I was expecting."