The Unitarian Society was established in 1791. The term Unitarian began being used in Europe at the beginning of the 17th century. John Biddle (1615-62) is considered to be the first minister to establish a Unitarian congregation in Britain. Another early supporter was Theophilus Lindsey (1723-1808), who built the Essex Street Chapel in London in 1778. However, it was the Nonconformist minister and scientist, Joseph Priestley, who became the most important proponent of unitarianism in 18th century England. After his home was destroyed by a mob in 1791, Priestley emigrated to America.
The Unitarians drew their membership to a large extent from the scientific professions and their outlook tended to be rational and individualistic. The original intentions of the movement was to unite all Non-conformist groups but this ended in failure. There is no set doctrinal beliefs that all Unitarians agree on. In fact, the most important aspect of Unitarianism is the right of individuals to develop their own religious opinions. Therefore the bond between them consists more in their anti-dogmatism than in any uniformity of belief. However, Unitarians tend to believe that Jesus Christ was a human religious leader to be followed but not worshipped. Unitarians argued that Jesus is the "great exemplar which we ought to copy in order to perfect our union with God".
Unitarians believed that social evils were humanly created, not God inflicted, and therefore could be remedied by human efforts. Unitarians were strong advocates of democracy and argued that each congregation should manage itself without outside control. This included the power to select and discharge ministers.
In the the late 18th and early 19th century, Unitarians were closely identified with the campaign for social and political reform. Unitarians such as Joseph Priestley, Jeremy Bentham, Robert Wedderburn, Harriet Martineau, James Martineau and John Stuart Mill were all advocates of universal suffrage. Other leading radicals of the period such as Tom Paine and Thomas Muir were described by their critics as Unitarians. After the publication of Paine's The Rights of Man, religious radicals in London formed the Unitarian Society to promote the cause of parliamentary reform.
Unitarian congregations developed mainly in large industrial cities such as Manchester, Birmingham and Leeds. Growth was slow and by 1851 there were only 229 congregations with about 30,000 members. However, they had considerable influence owing to the prominence of Unitarians in British Industry (Josiah Wedgwood, John Marshall, Thomas Ashton, Samuel Fielden, George Courtauld, Samuel Courtauld, Peter Taylor, Samuel Oldknow, Henry Tate, Charles Booth, etc.) and in Parliament (John Fielden, Robert Hyde Greg and Peter Alfred Taylor).
James Martineau, the brother of Harriet Martineau, was the leading English Unitarian in the middle of the 19th century. In his book The Rationale of Religious Enquiry (1836), Martineau argued that "reason is the ultimate appeal, the supreme tribunal, to the test of which even Scripture must be brought". William Gaskell, a Unitarian minister in Manchester, and the husband of the novelist Elizabeth Gaskell, was another important figure during this period.
In the 19th century Unitarians were very active in the movements for factory reforn, public health, prison reform, temperance, women's rights and the abolition of slavery. Unitarian reformers included Edwin Chadwick, Florence Nightingale, Jenkin Lloyd Jones and Charles Booth.
In the religious census of 1851 there were 3,153,490 Protestant Nonconformists. This included 37,156 Unitarians..
In the largest states, if the abuses of government should, at any time be great and manifest; if the servants of the people, forgetting their masters, and their masters' interest, should pursue a separate one of their own; if, instead of considering that they are made for the people, they should consider the people as made for them; if the oppressions and violations of right should be great, flagrant, and universally resented; if the tyrannical governors should have no friends but a few sycophants, who had long preyed upon the vitals of their fellow citizens, and who might be expected to desert a government, whenever their interests should be detached from it: if, in consequence of these circumstances, it should become manifest, that the risk, which would be run in attempting a revolution would be trifling, and the evils which might be apprehended from it, were far less than these which were actually suffered, and which were daily increasing; in the name of God, I ask, what principles are those, which ought to restrain an injured and insulted people from asserting their natural rights, and from changing, or even punishing their governors that is their servants, who had abused their trust; or from altering the whole form of their government, if it appeared to be of a structure so liable to abuse?
To say that these forms of government have been long established, and that these oppressions have been long suffered, without any complaint, is to supply the strongest argument for their abolition. Nothing can more justly excite the indignation of an honest and oppressed citizen, than to hear a prelate, who enjoys a considerable benefice, under a corrupt government, pleading for its support by those abominable perversions of scripture, which have been too common on this occasion; as by urging in its favour that passage of St Paul, "The powers which be are ordained of God", and others of a similar import. It is a sufficient answer to such an absurd quotation as this, that, for the same reason, the powers which will be will be ordained of God also.
It will be said, that it is opening a door to rebellion, to assert that magistrates, abusing their power, may be set aside by the people, who are of course their own judges when that power is abused. May not the people, it is said, abuse their power, as well as their governors? I answer, it is very possible they may abuse their power: it is possible they may imagine themselves oppressed when they are not: it is possible that their animosity may be artfully and unreasonably inflamed, by ambitious and enterprising men, whose views are often best answered by popular tumults and insurrections; and the people may suffer in consequence of their folly and precipitancy. But what man is there, or what body of men (whose right to direct their own conduct was never called in question) but are liable to be imposed upon, and to suffer in consequence of their mistaken apprehensions and precipitate conduct?
English history will inform us, that the people of this country have always borne extreme oppression, for a long time before there has appeared any danger of a general insurrection against the government.
(2) Henry Snell, Men Movements and Myself (1936)
Although I had become a member of the National Secular Society, and no longer believed in the verbal inspiration of the bible, in miracles, the biblical story of creation, or several other orthodox doctrines, I had arrived at no settled opinions concerning the mystery of life, or of the origin, nature, and government of the universe. Consequently, the Unitarian chapel with its scholarly approach to these great problems, with its tolerance for those of other faiths, and with its record as a progressive force in the civic life of the town, made a quick and strong appeal to me, and I entered into its gates with thanksgiving.