A red-haired extremist who fantasized about poisoning "non-Aryans" and killing Prince Charles has been convicted of planning terrorism.

British prosecutors say 37-year-old Mark Colborne wrote in his diary of plans to assassinate the heir to the British throne with a high-powered rifle, and compared himself to Norwegian mass killer Anders Breivik.

He also wrote of carrying out a cyanide attack on "non-Aryans" and collected chemicals and books on poisons.

Prosecutors say Colborne felt alienated and marginalized as a white, red-haired man. He claimed in his defense that his writings were "angry rants" made when he stopped taking medication for depression.

Colborne was arrested in June 2014, but a trial jury failed to reach a verdict. After a retrial, jurors in London convicted Colborne Tuesday of preparing terrorist acts.