Mr Salman Rushdie was in hiding under police protection last night and unrepentant about the contents of his novel, The Satanic Verses, which yesterday provoked the Iranian religious leader, Ayatollah Khomeini, to call for his execution.
The Foreign Office hopes for clarification from the Iranian government, amid fears that Islamic anger at the book could overshadow improving relations between London and Tehran and efforts to free hostages believed held by pro-Iranian factions in the Lebanon.
The Iranian threat to Mr Rushdie was broadcast by Tehran radio, which quoted the Ayatollah saying: "I inform the proud Muslim people of the world that the author of the Satanic Verses book which is against Islam, the Prophet and the Koran, and all those involved in its publication who were aware of its content, are sentenced to death. I ask all the Muslims to execute them wherever they find them." Assailants who died in the process would be instant martyrs to Islam. The Iranian prime minister, Mr Mir-Hossein Mousavi, pronounced today a day of mourning against the book.
The threat to Mr Rushdie's life is the latest twist in a saga of increasingly violent opposition to his book by Muslims who insist it is blasphemous about the prophet Mohammed. It has been banned in India, where Mr Rushdie was born a Muslim in 1947, and in South Africa. Last month, copies were burned in Bradford, Yorkshire, and last weekend five protesters were shot dead by police during demonstrations in Islamabad, Pakistan.
Mr Rushdie asked for police protection immediately after the Ayatollah's threat. Last night Scotland Yard would only say the threat was being taken seriously.
However, Mr Rushdie was not cowed. "Frankly I wish I had written a more critical book," he said during a television interview. "A religion that claims it is able to behave like this, religious leaders who are able to behave like this, and then say this is a religion which must be above any kind of whisper of criticism, that doesn't add up."
Strength of feeling against Mr Rushdie was expressed yesterday by some leaders of Britain's Muslim community in comments which several Conservative MPs claimed amounted to incitement to murder.
Mr Iqbal Sacranie, of the UK Action Committee on Islamic Affairs, said: "Death, perhaps, is a bit too easy for him his mind must be tormented for the rest of his life unless he asks for forgiveness to Almighty Allah."