In 1975, Dr Ljubo Sirc, my colleague at Glasgow University and a strong critic of Communist policies in his native Yugoslavia, was informed that the Yugoslav authorities had taken strong action in order to silence him. Two members of the security police had gone to the home of his elderly mother in Slovenia and confiscated her passport. She was told that it would not be returned unless her son refrained from all critical comment in future. He firmly refused to submit, but this meant that, as he himself would face immediate imprisonment if he were to return to Slovenia and as his mother could no longer meet him abroad, she could never expect to see him or his family again.
As it happened, I had an opportunity to tell Harold Wilson about this action when we were both dining at University College, Oxford. He was indignant at such harsh treatment and said he would have the matter raised. Notwithstanding the many other claims on a prime minister's attention, he found time to do so. Soon afterwards, Mrs Sirc had her passport returned.