The crisis-hit Pan-Orthodox Council due to start in Crete on Saturday has been dealt a mortal blow by the withdrawal of the Russian Orthodox Church.

The council was designed to bring together the 14 'autocephalous' or self-governing Eastern Orthodox Churches to iron out historical issues and address key theological and social questions. However, a succession of withdrawals put the standing of the council in doubt and now the defection of the ROC – the fifth Church to pull out, as well as the largest and most influential of all the Orthodox Churches – means the council can no longer claim to be authoritative.

In its official statement, the ROC refers to the withdrawal of the four Churches – Antioch, Georgia, Serbia and Bulgaria and says: "In this situation, the necessary ground for convening a Holy and Great Council... is obviously absent."

It says: "The only possible decision in this case is to continue the preparation of the Holy and Great Council with the subsequent achievement of pan-Orthodox consent to its convocation at a different date."

If the proposed council goes ahead anyway, the statement says, the ROC will not attend.

However, the chairman of the department of the external church relations, Metropolitan Hilarion, told the RT news service: "I do not see the current situation as catastrophic. I believe it is one of the stages of preparation for the Pan-Orthodox Council. It's not a fault that this preparation was as smooth as we wanted it to be. And we do not believe that the whole idea of the council should be abandoned. We simply believe that it should be better prepared."

He said: "There are many problems among various Orthodox Churches... These disagreements might seem small but, for historical churches, these are important issues.

"One Church after another declares that it is not participating, which means there will be no consensus, which means it is no longer a Pan-Orthodox Council. And we believe that the only way out of this difficult situation is to postpone the council," Hilarion said.