As far as I recall, it was Belgian, & was narrated by Kenneth Robinson.....
The planet in question was inhabited by 2 species, The Shadoks (the spiky ones), & The Gibli (intellgent round pacifists).
The Shadoks were belligerant, but very stupid (One episode posed the question as to what was the highest number a Shadok could count to... The Answer was 4).
The series ended with the Gibli leaving the planet, in a DIY Starship, as the planet was about to destroy itself...
The Shadoks stay behind, as they ignore the Gibli's warning, & die with the planet....
