Prime Barrier

The Prime Barrier is a part of the physiological makeup of Homo superior that prevents them from deliberately killing a living thing.

Original Series

The Prime Barrier is first described in Part 1 of "The Slaves of Jedikiah", when Carol describes to Stephen that Tomorrow People "can't kill... well, not deliberately anyway."

1990's Series

In the first series, while talking to Lisa Davies aboard the The Ship, Adam Newman confirms the existence of the Prime Barrier in the series (though they don't give it a name) while relating how he got a shark bite because he was unable to defend himself from a shark even though he had a knife at the time.

Despite this, the Tomorrow People in this series do appear to overcome the Prime Barrier in places. This is usually indirectly, such as Adam intentionally saving an antidote instead of Dr Culex when she fell off a railing, resulting in her death. However, in the episode "The Living Stones" the team does intentionally destroy a group of hostile alien invaders.

U.S. TV Series

In the pilot episode, an Ultra field agent is goaded in attempting to shoot Jedikiah Price, but drops the gun after experiencing pain from the Prime Barrier.

When a bully attacks Stephen Jameson at school, Stephen retaliates by using telekinetic force to choke the boy, but the Prime Barrier kicks in and briefly renders Stephen unconscious.

Ultra's Annex Project allowed John Young and Killian McCrane to overcome the Prime Barrier, granting them the ability to kill.

In "Sorry For Your Loss", Darcy Nichols used a gun to shoot Ultra agents in the leg, demonstrating that Tomorrow People are able to use deadly weapons if their intent is non-lethal.

In "Limbo", a Tomorrow Person named Michael turns out to be a serial rapist. He beats Stephen unconscious, then throws him into a sewer. This shows that the Prime Barrier only extends to the deliberate taking of a life, and does not prevent causing physical or mental harm, nor actions that indirectly result in death.