They were already in some distant land. They certainly didn't go back to England to face trial.
If he stayed here, He would have been locked up and the trial would have been closed door...for national security of course. You wouldn't have any nationally televised interviews with him, you wouldn't see him at all. He would not be labeled a hero, he would simply be called a terrorist and none of us would be allowed to hear his story...all we would get is the "official" story.