The Cretin Gene by Brendan Ball

Al Horowitz, ageing cartoonist and self-styled ninja, is catapulted from peaceful dotage to national notoriety when a dissident's assassin disguises himself as a benign Horowitz vegetable character, the opening gambit of a plot to cretinise the populace through customised junk food additives and media programming. Reviled in the press and hunted as a murderous agent of North Korean dictator Boh Gi Mon, Horowitz is soon on the run with his nephew 'The Kid', a reclusive arch-nerd geneticist, each seeing the other as in childlike need of his own selfless guidance. As the zombified masses rise in effigy-burning rage against Horowitz and his supposed fifth-columnist cadre, young lab colleague 'Technicia' joins the fight to save intelligent life in the UK while also juggling two male egos and her own secret of the heart.