The phrasing has echoes of the New Testament passage: "He that is not with me is against me" - a passage used by President George Bush when addressing a joint session of Congress nine days after 9/11.

The Muslims call instead for the emphasis to be on the shared characteristics of world's two largest faiths.

The letter, addressed to Pope Benedict XVI, to the Orthodox Church's Patriarch of Constantinople, Bartholomew 1 and all the other Orthodox Patriarchs and to the Archbishop of Canterbury Dr Rowan Williams and the leaders of all other Protestant churches worldwide, will be rolled out around the world this morning in a series of press conferences beginning in Jordan. It is supported by the Bishop of London, the Right Rev Richard Chartres.

It is expected to be followed by a joint conference between Muslim and Christian world leaders at on "neutral" ground, such as at an American university.

"Finding common ground between Muslims and Christians is not simply a matter for polite ecumenical dialogue between selected religious leaders," the Muslim scholars say, noting that Christians and Muslims make up over a third and a fifth of humanity respectively.

"Together they make up more than 55 per cent of the population, making the relationship between these two religious communities the most important factor in contributing to meaningful peace around the world. If Muslims and Christians are not at peace, the world cannot be at peace."

The Muslims even quote passages verbatim from the Bible, extremely rare in a publication of this kind and at this level and an indication of their resolve to bring the two faiths together and end the present tensions between them.

The letter continues: "With the terrible weaponry of the modern world; with Muslims and Christians intertwined everywhere as never before, no side can unilaterally win a conflict between more than half of the world's inhabitants. Thus our common future is at stake. The very survival of the world itself is perhaps at stake."

It says: "And to those who nevertheless relish conflict and destruction for their own sake or reckon that ultimately they stand to gain through them, we say that our very eternal souls are all also at stake if we fail to sincerely make every effort to make peace and come together in harmony."

Concluding with a quote from the Koran, the scholars say: "So let our differences not cause hatred and strife between us. Let us vie with each other only in righteousness and good works."

The letter is being sent out today by the Royal Aal al-Bayt Institute for Islamic Thought in Amman, Jordan.

Among those launching the letter in the UK will be two world leading figures in interfaith dialogue Professor David Ford and Aref Ali Nayed.

Professor David Ford is Regius Professor of Divinity, and Fellow of Selwyn College, University of Cambridge. Professor Ford is also the Founding Director of the Cambridge Inter-Faith Program and led this year's international inter-faith conference at Lancaster House in June on 'Islam and Muslims in the World Today'.

Aref Ali Nayed is a leading theologian and senior adviser to the Cambridge Inter-Faith Program. He is formerly Professor at the Pontifical Institute for Arabic and Islamic Studies in Rome, and the International Institute for Islamic Thought and Civilization in Malaysia.

Signatures include Shaykh Sevki Omarbasic, Grand Mufti of Croatia, Dr Abdul Hamid Othman, adviser to the Prime Minister of Malaysia and Dr Ali Ozak, head of the endowment for Islamic scientific studies in Istanbul, Turkey. They also include Shaykh Dr Nuh Ali Salman Al-Qudah, Grand Mufti of Jordan and Shaykh Dr Ikrima Said Sabri, former Grand Mufti of Jerusalem and Imam of the Al-Aqsa Mosque.

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