Born in Sutton-on-Trent in Nottinghamshire, the son of agricultural workers, Harry Snell was educated at his local village school before beginning work as a farm hand at the age of eight.

He rejected the austere and literalist Anglicanism of his up-bringing, but retained some religious faith and decided to join the Unitarian Church, impressed by its scientific approach to Christian doctrine and its progressive and tolerant values.

Eventually Unitarianism would grow even too strict for him, and he became an agnostic and member of the National Secular Society, and a "devoted advocate" of the Ethical Union (now Humanists UK).

[1] Of his ties to the British Ethical movement, he once remarked: Although political and Labour questions arrested my attention, and made constant demands on my time and energies, my deepest and most abiding interests were in religion and ethics, and to these great subjects that the best thought and work of my life has been given.After hearing Annie Besant address a meeting of the Secular Society on the subject of socialism, Snell joined the Social Democratic Federation.

He worked on John Burns' campaign for Parliament in 1885, and began to address public meetings himself, appearing alongside the likes of Henry Hyndman, Tom Mann, Eleanor Marx and Ben Tillett.

[citation needed] In 1890, Snell began social work for the Woolwich Charity Organisation Society, and later became secretary to the director of the London School of Economics.

He joined the Independent Labour Party and, in 1894, the Fabian Society, travelling extensively around Britain to lecture on socialist topics with speakers including Ramsay MacDonald and Bruce Glasier.

Snell also dissented from the Commission's claims that Palestine was overcrowded, agreeing with reports published two years earlier that had found the area to be under-populated and greatly under-cultivated.