William Henry Barnes was baptised on 8 April 1827 at Manchester, Lancashire, England. He was the son of Jane Bonsell and her husband, George Barnes, a labourer. William, also known as Bill or Billy, had some education; his few surviving letters are well written. He may have served an apprenticeship in the metal trades. Manchester had a long tradition of labour militancy and William was aware of what could be achieved when workers united. In 1842, when he was a teenager, 50,000 workers in Manchester went out on a general strike organised by Chartist leaders.
William Barnes married Elizabeth Colley on 10 September 1854 at West Ham, Essex. They had eight children, but three daughters died of scarlet fever in 1864. In November 1857 the Barnes family emigrated to Canterbury, New Zealand, on the Roehampton, arriving at Lyttelton on 7 March 1858. Barnes was described as a smith on the passenger list.
In 1859 there was an upsurge of unemployment in the province and skilled immigrants turned to roadmaking. Barnes called a meeting of concerned workers in early September to discuss the depression and propose relief measures. An orderly crowd of about 200 attended. They resolved to warn prospective immigrants, in placards and newspaper articles, of the true state of affairs in Canterbury.
Barnes and his supporters became the focus of criticism: the Lyttelton Times ridiculed 'the lounging new-chum.' After a second meeting in September Barnes was accused of intending 'to crush the Government and the capitalist', a rather hysterical reaction to his moderate demands. He wanted a temporary halt to immigration, offices where employers could meet the unemployed, and more roadworks.
In 1862 Barnes started the Railway Foundry in Manchester Street, Christchurch, and took A. C. Newton into partnership. Within the next few years he became active in the Canterbury Working Men's Association. As secretary in 1866 he publicly challenged another member, S. P. Andrews, then standing for the provincial council and a future member of Parliament. Andrews advocated compulsory secular education and manhood suffrage. Barnes opposed these policies, but found himself out of step with popular opinion. Subsequently he resigned as secretary, and was replaced by Andrews. Barnes stood for the Christchurch City Council in 1868, advocating a ward system and underground drainage, but won few votes.
Meanwhile Barnes's business was moderately successful. In 1867 five artesian wells were sunk for the Christchurch Borough Council. In the same year a fire alarm was erected near the fire station on a structure 66 feet high, which also acted as a look-out. By 1869 the foundry had several buildings, with casting, turning, pattern and coppersmith shops, and a smithy. The partnership with Newton had dissolved by 1868, and a year later Barnes faced bankruptcy proceedings, but he was not judged insolvent. He sold his foundry to Scott Brothers in 1872 and moved to Temuka, later returning to Christchurch. He continued to work as a blacksmith and in 1878 built a dredge for the Waimakariri Harbour Board.
Barnes had a keen interest in the Canterbury Rifle Volunteers, which he joined in 1861. He was first a private, and later a gunner when his company became an artillery corps. He often entered rifle-shooting competitions, and won the Bealey Cup for his company in 1870. He served on the Volunteer General Committee and on the council of the Canterbury Rifle Association, and donated prizes for competitions.
Barnes was Canterbury's first significant labour leader. Discredited politically, he threw his energies into his business and the Volunteers. His wife died on 16 May 1911 and he probably spent his last years in Nazareth House, an old people's home in Christchurch. He died there on 23 July 1918.