The poet and playwright Adrian Mitchell, in whom the legacies of Blake and Brecht coalesce with the zip of Little Richard and the swing of Chuck Berry, has died of heart failure at the age of 76. In his many public performances in this country and around the world, he shifted English poetry from correctness and formality towards inclusiveness and political passion.

Mitchell's original plays and stage adaptations, performed on mainstream national stages and fringe venues, on boats and in nature, add up to a musical, epic and comic form of theatre, a poet's drama worthy of Aristophanes and Lorca. Across the spectrum of his prolific output, through wars, oppressions and deceptive victories, he remained a beacon of hope in darkening times.

He was a natural pacifist, a playful, deeply serious peacemonger and an instinctive democrat. "Most people ignore most poetry because most poetry ignores most people," he wrote in the preface to his first volume, Poems (1964). For all his strong convictions, he abhorred solemnity. From Red Pepper, a small leftwing magazine, he gleefully accepted a nomination as "shadow Poet Laureate", and demolished royalty, cultural fashions and pretensions in monthly satirical sallies.

He was born in north London "near Hampstead Heath", which he loved like an extra limb for the rest of his life, walking it daily with his dog Daisy, "the dog of peace". His mother Kathleen was a nursery school teacher, his father Jock a research chemist, who underwent the agony of the first world war, an experience which helped to plant in Adrian a hatred of war.

He went through his own childhood version of hell in a school full of bullies, whose playground he characterised as "the killing ground". His next school, Greenways, was idyllic, and there he staged his first play at the age of nine, and went on writing and performing plays, with his friend Gordon Snell. His schooling was completed as a boarder at Dauntsey's in Wiltshire.