His name is Matthew, he is 26 years old, and his supporters hope to take his case to the European Court of Human Rights.
But he won't be able to give evidence on his own behalf - since he is a chimpanzee. Animal rights activists led by British teacher Paula Stibbe are fighting to have Matthew legally declared a 'person' so she can be appointed as his guardian if the bankrupt animal sanctuary where he lives in Vienna is forced to close.
An anonymous businessman has offered a substantial amount to cover his care, but under Austrian law only humans are entitled to have guardians.
The country's supreme court has upheld a lower court ruling which rejected the activists' request to have a trustee appointed for Matthew.
So now 36-year-old Miss Stibbe and the Vienna-based Association Against Animal Factories have filed an appeal with the European Court of Human Rights in Strasbourg.
The insists that the chimp needs legal standing so a guardian can be appointed to look out for his interests - especially if the sanctuary shuts down.
Miss Stibbe, who is from Brighton but has lived in Vienna for several years, says she is not trying to get the chimp declared a human, just a person.
'Everybody who knows him personally will see him as a person,' she said.
'In his home in the African jungle, he would have been well able to look after himself without a guardian.
But since he was abducted into an alien environment, traumatised and locked up in an enclosure, it did become necessary for me to act on his behalf to secure the donation money for him and to avoid his deportation.
'Since he has no close relatives, I am doing this as the person closest to him.'
The legal wrangle began in February 2007, when the sanctuary where Matthew lives with another chimp, Rosi, plus a crocodile filed for bankruptcy protection.
Activists want to ensure the apes do not wind up homeless. Both were captured as babies in Sierra Leone in 1982 and smuggled to Austria for use in pharmaceutical experiments.
Customs officers intercepted the shipment and turned the chimps over to the shelter. Their upkeep costs £4,000 a month.
Donors have offered to help, but under Austrian law, only a human can receive personal gifts.
Organisers could set up a foundation to collect cash for Matthew, whose life expectancy in captivity is about 60 years.
But they argue that only personhood would ensure he is not sold to someone outside Austria, where he is protected by strict animal cruelty laws.
In dismissing the activists' request to get a guardian for Matthew, a lower court ruled that the chimp was neither mentally impaired nor in danger - the legal grounds required for a guardian to be appointed.
It did not directly address the issue of whether a chimpanzee can be considered a person.
Eberhart Theuer, the animal rights group's chief legal adviser, said there is a legal precedent to appoint a guardian for an individual incapable of expressing himself.
'As long as Matthew is not recognised as a person, he could be sold abroad or killed for economic reasons,' Theuer said.
'His life depends on this decision. This case is about the fundamental question: Who is the bearer of human rights? Who is a person according to the European Human Rights Charter?'
A spokesman for the court in Strasbourg said: 'Any application regarding this chimpanzee will be considered at a primary level by a magistrate and a lawyer before we decide whether it deserves a full-blown hearing.'
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