A posthumous pardon was not considered appropriate as Alan Turing was properly convicted of what at the time was a criminal offense. He would have known that his offense was against the law and that he would be prosecuted. It is tragic that Alan Turing was convicted of an offense which now seems both cruel and absurd–particularly poignant given his outstanding contribution to the war effort. However, the law at the time required a prosecution and, as such, long-standing policy has been to accept that such convictions took place and, rather than trying to alter the historical context and to put right what cannot be put right, ensure instead that we never again return to those times.
Звучит весьма неоптимистично, увы.
Вот несколько ссылок по теме:
Статья в Guardian
Статья на openculture, там есть ещё и фильм BBC 1996 года про Тьюринга
Статья про Тюринга по-русски