In his autobiography, Footprints, Selwyn Selwyn-Clarke describes his arrest at the French Hospital early in the morning of May 2, 1943. He hints at the prolonged torture he was subjected to in order to make him confess (falsely) that he was head of British espionage in Hong Kong. He writes:
The first series of treatments was followed by something that passed for a trial, though it was merely a sentence of execution; and to this I could only reply: ‘The sooner the better. I’m extremely tired of your methods of investigation’.
The Japanese felt affronted by Selwyn-Clarke’s suggestion that he would welcome the work of the executioner, so continued their ‘investigations’, while keeping the death sentence in place.
At some point, he was transferred from his cell in the former Supreme Court Building to Stanley Prison:
In Stanley Prison, some sixteen months after my first trial, I was given another. It was more formal this time, in the sense that there seemed to be two judges, assisted by an advocate-general, all in military uniform…My prison sentence, which had never before been delimited, was extended for another three years, but the capital charges had been dropped.
Selwyn-Clarke was tried as part of a group of about 40, one of whom was the former editor of The Hong Kong Daily Press, Neil Esmond Hunter. The Japanese refused to intern Hunter – who’d asked them to do so – because, although a British subject he had Singhalese nationality. On January 12, 1944, he was arrested, and soon accused of being a British spy, which he denied, in spite of brutal torture. The Kempeitai then changed the accusation to ‘spreading anti-Japanese propaganda’, and it was presumably on this charge that he found himself being tried in the same group as Selwyn-Clarke. According to Hunter, this trial took place on August 29. (He claims that Selwyn-Clarke got two years; it’s not impossible that, speaking almost exactly a year later, he was right – Selwyn-Clarke was writing after thirty years had gone by, and the exact length of his sentence was academic, as both he and Hunter were amnestied in early December 1944.)
Assuming Hunter’s dating is correct, then Selwyn-Clarke’s first trial would have taken place on April 29, 1943, which was a few days before his arrest on May 2. Of course, he writes ‘some’ 16 months, which allows a degree of latitude, but I think it more likely that his second trial was 16 months after his arrest.
While on leave in the UK after his ordeal in the war, Dr. Selwyn-Clarke gave a talk at the annual dinner of the Isle of Wight Medical Association held at Ryde Town Hall. The report of this speech in the BMJ Supplement of June 8, 1946 states that the formal trial took place ‘Sixteen months after his original incarceration‘ (italics mine).
 Footprints, 1975, 85.
 Footprints, 91.
 Russell Clark, An End To Tears, 137-142.