Abdullah Öcalan’s message, which follows four decades of guerrilla warfare, will have far-reaching implications across the Middle East

The ageing leader of a Kurdish militant group imprisoned on a remote Turkish island has called on the group to disarm and dissolve itself, signalling the start of a fragile peace with Turkey after four decades of guerrilla warfare, attacks and reprisals.

Abdullah Öcalan, a founding member of the Kurdistan Workers’ party (PKK), a group long regarded as a terrorist organisation in Turkey as well as in Britain and the US, issued the message in a letter read out by allies in Istanbul.