He was born at Yoxford in Suffolk and was baptised on 12th November 1820. His father, John, a solicitor, married to Julia, died when he was fourteen years old. Goodwyn, he never used his first Christian name had no formal school education but read widely. He eschewed the professions and followed a career of social and political radicalism, reputedly addressing small audiences of agricultural labourers when aged sixteen.
Barmby claimed credit for founding the East Suffolk and Yarmouth Chartist council in September 1839. In December he was elected delegate to the Chartist convention and in 1840 and 1841 he was re-elected, though alienated from political radicalism by this time. Already a correspondent of the Owenites’ New Moral World (writing on language reform and Charles Fourier), in 1840 he visited Paris with a letter of introduction from Owen. There he studied French social organisation and claimed by this to have originated the English term ‘communism’. He married at Marylebone on 4th October 1841 Catherine Isabella Watkins (1816/17–1853), who, under the signature of Kate, contributed to the New Moral World. They had a son, Moreville, and a daughter. On 13th October 1841, Barmby founded the Communist Propaganda Society and designated 1841 Year 1 of the new communist calendar. The Universal Communitarian Association followed, promoted by the monthly Educational Circular and Communist Apostle. In 1842, he founded and almost single-handedly wrote the monthly Promethean, or, Communitarian Apostle, which also promoted rational marriage and universal suffrage, and lectured at the ‘communist temple’ at Marylebone Circus, Marylebone, Middlesex. Out of this activity and through his contact with James Pierrepont Greaves (with whom he published the New Age, or, Concordian Gazette, the journal of Greaves’s own Ham Common community), Barmby established the Moreville Communitorium at Hanwell in 1842. The following year, he issued his Communist Miscellany, a series of tracts written by himself and his wife, and founded the weekly Communist Chronicle, which also supported the German communist Wilhelm Weitling.
Thomas Frost described Barmby at this time as ‘a young man of gentlemanly manners and soft persuasive voice, wearing his light brown hair parted in the middle after the fashion of the Concordist brethren, and a collar and necktie à la Byron’. With the Communitorium renamed the Communist Church by 1844, Barmby began his move towards sectarianism; he conducted a propaganda tour in the north and midlands in the winter of 1845–6 and forged links with the Dublin sect of White Quakers. In 1845 he combined with Frost to revive the Communist Chronicle, for which he translated some of Reybaud’s ‘Sketches of French socialists’, and wrote a philosophical romance entitled The Book of Platonopolis, which sought to fuse utopian fiction and modern science. However, Frost soon tired of Barmby’s sectarianism and separated from him in 1846, to establish the Communist Journal.
Frost’s competition with Barmby destroyed both journals but Barmby continued to proselytize in Howitt’s Journal, and contributed to the People’s Journal, Tait’s Magazine, Chambers’s Journal, and other periodicals. In 1847, he lectured at the Farringdon Hall, Poplar, London, and in July he convened a meeting at the John Street Institute in support of the Icarian settlements in Texas. It was probably to his friendship with W. J. Fox MP that Barmby owed his introduction to Unitarianism, following his post-1848 disillusionment with communism. After his return from revolutionary Paris, where he had gone in 1848 as Howitt’s representative and as the envoy of the Communist Church, he was successively minister at Southampton, Topsham, Lympstone, Lancaster, and Wakefield. He was one of the best-known ministers in the West Riding of Yorkshire and held his post in Wakefield for twenty-one years from 1858, leading the Wakefield congregation which included the industrialist Henry Briggs. He was also secretary of the West Riding Unitarian mission. On 20th July 1861, Barmby married his second wife, Ada Marianne Shepherd, daughter of the governor of Wakefield gaol, with whom he had a daughter.
Barmby always retained his liberal political convictions, and was closely involved in the Wakefield Liberal Association from 1859: he chaired its North Westgate ward committee that year and the full town committee in 1860. In 1867, he organised a large public meeting there in support of parliamentary reform and joined the National Association for Women’s Suffrage. Barmby was a member of the council of Mazzini’s International League and also supported Polish, Italian, and Hungarian freedom. Barmby wrote several volumes of pastoral poetry: The Poetry of Home and Childhood (1853), Scenes of Spring (1860), and The Return of the Swallow (1864). His devotional works included Aids to Devotion (1865), the Wakefield Band of Faith Messenger (1871–9), committed to the advance of theological liberalism, and a large number of hymns and tracts.
In 1879, Barmby’s health deteriorated. He retired to Yoxford but continued to hold intensely devotional private services. He died there on 18th October 1881, and was buried at the cemetery of Framlingham, Suffolk. His second wife survived him.
 A. L. Morton The English utopia, 1952, pages 132–8, W. H. G. Armytage Heavens below: utopian experiments in England, 1560–1960, 1961, pages 196–207, The Inquirer, 29th October 1881, page 721, W. Blazeby Unitarian Herald, 9th November 1881, page 358, G. J. Holyoake The history of co-operation, volume 1, 1875, pages 228–30 and T. Frost Forty years’ recollections, 1880.
 T. Frost Forty years’ recollections, 1880, page 57.