Öçalan had remained in total isolation on Imrali Prison island for years, with no direct contact, and even longer since any appearance in public.

It is thought he will make a call for the disarmament of the PKK, or some kind of peace process with the Turkish government.

The announcement may be an attempt to broker a wider peace within Northern Syria and also Iraq, where PKK guerillas are fiercely resisting Turkish invaders.

The public address is due for February 15th, the anniversary of the 1999 conspiracy in which the CIA kidnapped Öçalan whilst he attempted to flee to Europe.