In the late 18th and early 19th centuries trade unionism (or the 'combination' of workers in an attempt to improve their wages and working conditions) was seen by many in authority to be a form of Jacobinism - a subversive, potentially revolutionary activity that could threaten the state and social order. In 1799 the government of William Pitt the younger passed the Combination Act (reinforced in 1800) which banned "unlawful combinations of workmen" - outlawing trade unionism and collective bargaining. In 1824 the Combination Act was repealed, but unions, though legal, were still regarded by the authorities to be a threat to property and the state.

In the early 1830s rural poverty, worsened by enclosure (the transfer of land held in common by the community to landowners by Acts of Parliament) and the introduction of labour-saving (and unemployment-causing) machinery, sparked protests and rioting across southern and eastern England. The riots of 1830, named after the fictional figurehead Captain Swing, included the destruction of machinery, arson attacks, mutilation of livestock and the sending of threatening letters, but caused no loss of human life and few casualties. Suspected rioters were however punished severely with death sentences (most of which were later commuted to transportation), transportation (forced labour in a British colony - usually Australia - for either life or a set period of years), or imprisonment.

In 1832, in the small Dorset village of Tolpuddle, an agreement was made at a meeting between the masters and working men that wages would be raised to the same levels as were paid in neighbouring districts - to 10 shillings a week. By the end of the year this agreement had been broken, with the support of the local magistrate, and wages were instead lowered - first to 8 shillings a week, then to 7, and finally to 6. In 1833, under a sycamore tree on Tolpuddle village green, local workers met and formed a union - the Friendly Society of Agricultural Labourers - and members later privately performed initiation ceremonies, giving membership of the union a form of ritual.

The ritual of initiation gave the authorities an opportunity to crush the newly formed union. Using a rarely used piece of legislation - the 1797 Unlawful Oaths Act - six of the most prominent founders of the union were arrested and charged with the 'administration of unlawful oaths'. The men were the brothers George and James Loveless, James Brine, James Hammett, Thomas Standfield and his son John Standfield. Most of the arrested men were regarded as a double threat to the established order - as well as being trade unionists, the majority of the arrested men were also religious dissenters - lay preachers or members of the congregation at the local Methodist chapel.

On 14 March 1834 the six men were tried at the Assize court at Dorchester and each sentenced to seven years transportation. The jury included the local MP (and brother in law of the Home Secretary) William Ponsonby and several magistrates who had signed warrants for the arrest of the defendants.

The case prompted major protests across the country. This print (a later copy of an engraving first published in 1834) shows the huge crowds which met peacefully at Copenhagen Fields, Islington, on 21 April 1834, to appeal against the sentence. The demonstration was organised by the Central Committee of the Metropolitan Trade Unions and included a procession through London to Kennington Common with a wagon carrying a petition with over 200,000 signatures (shown in the engraving). The Home Secretary Lord Melbourne refused to accept the petition, although it was successfully delivered a week later.

The engraving by W. Summers was dedicated to Thomas Wakley, MP, a leading campaigner on behalf of the 'Dorchester labourers' (later known as the Tolpuddle Martyrs), by the publisher, Isaiah Saunders. This version of the print is included in the archives of the National Union of Vehicle Builders (document reference: MSS.631/8/7).