ANKARA: When Turkish authorities arrested Kurdish militant leader Abdullah Ocalan two decades ago, it struck a blow to his outlawed separatist group but experts say his influence remains significant as a key player in any future peace deal.
Ocalan founded the Kurdistan Workers' Party (PKK) - blacklisted as a terror group by Ankara, the United States and the European Union - in 1978 with a group of fellow students to seek Kurdish autonomy.
The party became an armed group from 1984, with the objective of creating an independent Kurdish state. More than 40,000 people were killed during the PKK's insurgency.
Prior to his 1999 arrest, Ocalan was in exile in Syria until Damascus and Ankara reached an agreement in 1998 and he was forced to leave.
He was eventually caught in Kenya outside the Greek embassy in Nairobi on Feb 15, 1999 by Turkish secret service agents.
Now he is in a notorious prison on Imrali island off Istanbul and despite almost complete isolation remains a reference figure for the Kurdish cause not just in Turkey but across the region.
"Ocalan's arrest was initially a huge blow to the organisation, because he had controlled every aspect of the PKK and its activities and suddenly he was gone," said Aliza Marcus, author of the book "Blood and Belief: The PKK and the Kurdish Fight for Independence".
"In addition, his decision to suspend the war and basically give up on an independent Kurdistan - as he announced at his trial - added a whole new layer of confusion," she said.
But the PKK has been able to adapt, "partly because Ocalan was able to communicate from prison, through interviews and meetings with his lawyers", Marcus said.
"BAN ON VISITS"
For example, in 2013 Ocalan called for - using lawmakers from the pro-Kurdish Peoples' Democratic Party (HDP) as intermediaries - a ceasefire to allow peace talks between Ankara and himself to achieve a political settlement.
The fragile ceasefire collapsed in 2015 and bloody clashes resumed in the country's southeast.
After the 2016 failed coup, Ankara stepped up its fight against terror under a state of emergency and a decision "was officially taken to ban all visits to Imrali, both for his lawyers and family", one of Ocalan's lawyers, Ibrahim Bilmez, said.
But Ocalan has not had access to his lawyers since 2011.
More than 300 people in jail are on hunger strike calling for Ocalan to be given access to his family members and lawyers, including Leyla Guven, a pro-Kurdish Peoples' Democratic Party (HDP) lawmaker, according to the HDP.
Guven, 55, has been pressing ahead with the strike launched on Nov 8, although she was released from prison pending trial last month.
In a bid to appease the hunger-strikers, Turkish authorities allowed Ocalan's brother Mehmet to visit him last month for the first time since 2016.
"These hunger strikes put the state in difficulty because the demands are legitimate. This is why Ocalan's brother was sent to Imrali," Bilmez said.
"We have no information, only what Mehmet told us," the lawyer said, but Ocalan wanted the public to know he was "well".
According to Bilmez, there is a "psychological connection" between Ocalan and the Kurdish people, "and they draw strength from each other", meaning the PKK leader retains his influence and popularity.
"In the long run, one has the impression that the arrest paradoxically served the PKK and the Kurdish cause," said Hamit Bozarslan, director of studies at the Paris-based School for Advanced Studies in the Social Sciences.
Bozarslan added that the PKK was more popular today than at the time of his arrest.
"In the last 20 years, the PKK has become one of the two key references in the Kurdish sphere in the region; the Iraqi Kurdish government being the other," he said.
And Ocalan's presence goes beyond Turkey as well. Loyal followers refer to him as "Apo" or "Serok" (the chief) and his images are on show in northern Syrian areas controlled by the US-backed Syrian Kurdish People's Protection Units (YPG) militia.
Since the resumption of violence in 2015, President Recep Tayyip Erdogan's speeches regarding Kurdish militants have hardened, making the prospect of a negotiated solution to the conflict even more difficult.
But, stressing that circumstances can always change, Bozarslan said that if he wanted to renew dialogue, Erdogan will "have no other interlocutor" than Ocalan.