Abdullah Ocalan, the Kurdish leader imprisoned since being captured by Turkish special forces in 1999, could win a retrial today in a judgment which may provoke a political crisis in Turkey.
Judges at the European Court of Human Rights will rule in the case which has far-reaching implications for the government in Ankara and its ambitions to join the European Union.
The sole inmate of a Turkish island prison, Ocalan has appealed to the court in Strasbourg, claiming that he has been ill treated and did not receive a fair trial after he was snatched from hiding in Kenya.
A ruling in his favour would provoke a fierce domestic backlash in Turkey. The majority of the population regards the former PKK leader as the nation's most dangerous terrorist. As PKK leader he is blamed for masterminding a separatist revolt in the south-east during the 1980s and 1990s in which at least 30,000 people were killed.
But failure to observe the ruling would compromise Turkey's claims to have modernised its judicial system and place a big question mark over its bid to join the EU. The court's rulings are binding on all 46 members of the Council of Europe, which include Turkey.
Ocalan - who was seized by a special forces unit and flown to Turkey six years ago - was originally sentenced to death, but this was commuted to life imprisonment and capital punishment was abolished in Turkey in 2001.
The former PKK leader claims Turkey breached international rules by treating him inhumanely on his transfer to the Imrali prison near Istanbul in 1999, discriminating against him, denying him the right to a fair and independent trial and barring his legal representatives from contacting him after his detention. He remains in solitary confinement though the Turkish authorities argue this is partly for his protection.
The Strasbourg court's ruling comes at a sensitive time for the government of Recep Tayyip Erdogan, who leads the Islamic-based Justice and Development Party (AKP) and who has pressed ahead with sweeping reforms to try to win EU membership talks. About a dozen members of parliament have quit the AKP in the past few months, claiming the government is losing touch with the public.
There are continuing tensions between Mr Erdogan and his Foreign Minister and political rival, Abdullah Gul, who is seen as more moderate and closer to EU political values, but the AKP remains well ahead of other parties in the opinion polls and in any case does not face a general election until 2007.
In an effort to avoid the prospect of legal victory for Ocalan, a proposal was made to exclude cases dating before 2003 from retrials. But the Turkish constitution underwrites the supremacy of international law and this is almost certain to prevail.
The government rode out a storm of protest over the retrial of Leyla Zana and three other activists last year. They were freed after a Turkish court said the four did not receive a fair hearing at their original trial in 1994 when they faced charges of collaborating with Kurdish rebels.
Nevertheless, a ruling in favour of Ocalan would reinforce a growing impression in Turkey that European institutions are biased against them.
A slump in the proportion of the population in favour of EU membership reflects the fallout over the compromises made by the government to clear the path for talks.
Negotiations between the EU and Ankara are due to start in October and the Turkish government has agreed to extend a customs union to the Greek-controlled half of Cyprus which became a member of the EU last year.Reuse content