A question about a live action British children's science fiction or fantasy movie or television show from about 20 to 40 years ago.
reminds me of a live action movie or episode I saw part of on television sometime late in the previous millennium.
It was a British children's movie or show, so naturally the protagonist was a British child, a boy who looked about ten years old, give or take a few years, and the setting seemed roughly contemporary with the late 20th century when I watched it. This boy had a supernatural or super scientific friend, not necessarily a human being, who could teleport. I don't remember clearly but it is possible the friend could have been non corporeal.
The only plot I remember had the friend teleport with the boy into the Tower of London to the Jewel House housing the Crown Jewels. But they set off alarms so the "friend" teleported away, leaving the boy behind to be caught inside the Jewel House.
After a speedy trial, or perhaps no trial at all, the boy was being marched by the yeoman warders to the chopping block to be beheaded when the friend returned and helped the boy escape. Clearly the episode was not intended to be educational about the legal system.
Can any one identify this episode or movie?