Under Article 40 of the Constitution, “the publication or utterance of blasphemous, seditious, or indecent matter” is a criminal offence.

Mr Ahern insists blasphemy must remain a crime, unless the reference to it in the Constitution is removed. “It is already there in the 1961 Act, and it is in the Constitution and we have to comply with the Constitution. You are in derogation of your duty if you ignore the Constitution,” he told Opposition TDs.

The inclusion of the blasphemy clause was accepted by Government TDs and passed by nine votes to six during yesterday’s committee stage debate.

The change in the €100,000 fine to just €25,000 will be made during next week’s report stage debate.

Islamic countries could retaliate if the DPP did not prosecute some future alleged insult against Islam, he warned.

Describing the Church of Scientology as “a dangerous, crack-pot cult”, Mr O’Keeffe said he could be prosecuted in future if he described it as such outside of Dáil privilege.