A British man locked up in Ethiopia must be released imminently, a charity has urged, as a psychiatrist's report showed a serious deterioration in his mental health.
Andargachew "Andy" Tsege has been detained in the country since he was removed from an airport in Yemen in June 2014.
The father-of-three, who fled the country in the 1970s and sought asylum in the UK in 1979, had been a prominent critic of Ethiopia's ruling party.
He was sentenced to death in his absence in 2009 for allegedly plotting a coup - charges he and others deny.
A psychiatrist's assessment, compiled using reports from visits made to Mr Tsege by the British Ambassador, and information provided by his partner Yemi Hailemariam, concluded that there is an "urgent need" to remove him from his current conditions.
Mr Tsege, who is feared to be suicidal, is said to be confined in unhygienic quarters, with no access to a doctor or lawyer.
Dr Benjamin Robinson of South London and Maudsley NHS Trust, whose report legal charity Reprieve said is being used with Mr Tsege's permission, said the damage being done could soon become irreparable.
He wrote: " Once he is freed from prison, then the long work of psychological recovery can begin. He will require intensive psychotherapy with an experienced therapist, a full psychiatric assessment, and consideration of pharmacological treatment for his mental health problems.
"Until that time, he will worsen, will remain at risk of suicide, and his personality will continue to fracture until - even if he survives physically - he will be beyond psychological repair."
Dr Robinson said Mr Tsege appears "indifferent" to his conditions.
He added: " In sum, the new material with which I have been provided, confirms that Mr Tsege's mental health has declined precipitously since being detained in Ethiopia, due in large part to the particular meaning this has for him in the context of his life history and personality."
Reprieve has called on the British Government to urge Mr Tsege's release from prison.
The Foreign Office said it has raised Mr Tsege's case with the Ethiopian Government on 19 different occasions "making it clear the way he has been treated is unacceptable".
Stopping short of calling for his release, a Foreign Office spokeswoman said Mr Tsege must be given legal access.
She said: " We welcome the improvement in access to Mr Tsege, following the British Government's intervention, but it must be more regular and it must include access to a lawyer.
"Mr Tsege has still not been given an ability to challenge his detention through a legal process and so the Foreign Secretary has written formally to the Ethiopians requesting that they set out a timetable for the legal process. We will continue to provide consular support to Mr Tsege and his family."