Didn't care for Gielgud's private life, but his portrayal of Aaron Jastrow was one of the greatest performances I'd ever seen. The scene were he gives the sermon in Thereisienstadt about Job "The Stinking Jew" is one of the most powerful things you'll ever see.
When Gielgud escorts the little girl to the crematorium and she is reunited with her mother and waves goodbye to him, you see him choke up, then before he goes down inside, he takes one last look at the moon... great cinematography...