British kids's movie or TV show, teleporting into Tower of London

Question

A question about a live action British children's science fiction or fantasy movie or television show from about 20 to 40 years ago.

This question: YA: boy lives in Tower of London, foils plot involving holograms

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?

Answer 1

Could this be The Tomorrow People (1973), specifically the episode "The Medusa Strain: Part 2" which features teleportation, a trip to the tower of London and various hijinks that ensue.

As Stephen and Carol discover the world caught in a time-freeze, they hear Peter's telepathic cry for help. Jaunting to the Tower of London, they find Rabowski stealing the crown jewels. In the confrontation, Rabowski's group captures Carol and takes her along through the time arch, leaving Stephen to struggle with the beefeater. As Carol gets to know Peter and learns of their plight, the other Tomorrow People try to determine what's become of her. Meanwhile, Rabowski interferes with Jedikiah feeding Peter to the Medusa, so Jedikiah makes it clear who's really in charge of the spaceship now. To force Peter to help them in future time travels, Carol is put in a vacuum chamber to die.

Answer 2

Though it's a little older than you thought, this sounds very much like The Boy Who Turned Yellow from 1972 about the strange adventure of a British kid:

John (Mark Dightam) loses one of his pet mice, Alice, whilst on a school trip to the Tower of London. Upset back in class, he is sent home by his teacher for not paying attention during a lesson on electricity. Later that day on the London Underground, the train and everyone in it suddenly turns bright, vivid yellow. John's doctor (Esmond Knight) declares that the condition is harmless and should wear off soon, but that evening John hears noises from his television set and meets the eccentric yellow-coloured [adult] Nick (short for Electronic) (Robert Eddison).

The boy discovers that him and Nick can travel through electricity. So they zap themselves into the Tower of London through the beefeaters' television set to look for John's mouse, but the boy gets caught. He's then arranged to be beheaded, but escapes at the last minute (by cleverly saying that his last wish is to watch TV).

It's basically an hour-long educational film about electricity. It was also the final collaboration of Michael Powell and Emeric Pressburger (AKA The Archers). You can see the clip where the boy turns yellow here, and here's a clip where John and Nick prepare to teleport to the Tower (but end up in the soccer match that the beefeaters are watching, at first):