Bonar Thompson was popular in the mid-twentieth century as a political orator and commentator who reached a wide audience through theatre, radio and print.

He was born in Carnearney, County Antrim, illegitimate son of farm labourers Johnny Bambridge and Matilda Bonar. He was brought up by an elderly aunt, Eliza Thompson, who was as impecunious as his parents and also a strict fundamentalist Presbyterian . He was educated at nearby Ladyhill National School and when thirteen or fourteen joined his mother in Manchester, working at various jobs in shops, workshops, offices and as a “greaser” on the Grand Central Railway. All the time he was an avid reader, taking advantage of the Manchester Free public Library; he listened to open-air orators, and at the age of seventeen, made his first speech in Salford. He became involved with the unemployment movement, was arrested for smashing shop windows during a protest; and was sentenced to a year in Rochester Borstal. In 1910 he moved to London, where for the next four years he survived financially by collecting money after his speeches, and by selling pamphlets which dealt with mostly political issues but also such as his theory on birth control. 

He opposed the First World War and refused as a conscientious objector to answer his call-up papers, declaring himself to be a revolutionary socialist of years’ standing and totally opposed to the War as “the outcome of the greed and jealousy of the Capitalist Class.” He was sent to a labour camp in Wakefield Jail. After the war he spent some time living quietly in Scotland and the North-East (conscientious objectors were widely unpopular) but returned to London in 1924. He would address large crowds at the famous Speakers’ Corner in Hyde Park and was known as “The Prime Minister of Hyde Park”. He wrote poetry and articles for The Worker and published three autobiographical volumes: An Agitator of the Underworld; An Evangel of Unrest and Hyde Park Orator, though the biographical details often contradict each other. He took part in several radio shows, including Gossip Hour; In Town Tonight and Variety in a Taxi Cab, and in 1948 performed in a radio broadcast production of Coriolanus. In 1930 he launched as editor a review journal, The Black Hat, though this folded after only a handful of issues; an attempted revivification in 1947 was no more successful. Throughout the 1940s, he put on satirical one-man shows, with titles such as Macbeth with Pat Geary. In 1945 he toured abroad with Basil Langton's Travelling Repertory Theatre Company. Michael Foot, Labour journalist and politician and himself rather radical, was an admirer and paid tribute to him as a powerful influence.

His view of his own political outlook seemed to evolve: the self-declared Revolutionary Socialist of the First World War tribunal later became in his own description “neither right-wing, left-wing, centre, or any other part of the political chicken”. He died in London and was cremated at Golders Green in that city.