Who were the ‘middle-classes’?  George Kitson Clark rightly counselled caution when he pointed out that
Of course, the general expression ‘middle-class’ remains useful, as a name for a large section of society .... (but) it is necessary to remember that a belief in the importance and significance of the middle-class in the nineteenth century derives from contemporary opinion .... They do not always say clearly whom they have in mind, and since the possible variants are so great a modern writer should follow them with great caution.... 
The middle-classes can be distinguished from the aristocracy and gentry not so much by their income as by the necessity of earning a living, and at the bottom from the working-classes not by their higher income but by their property, however small, represented by stock in trade, tools or by their educational investment in skills or expertise. Yet, the divide that was emerging was not the Marxist division between aristocracy and bourgeoisie but
...a cultural one, between the patrician landowner, banker, lawyer, clergyman or merchant on the one hand and the plebeian tradesman and manufacturer on the other. 
There may have been considerable room for agreement between capital and labour in attacking the political monopoly of the aristocracy, an agreement that was frequently reinforced by shared local, political and religious loyalty. The alliance between capital and labour was, however, often fraught by fears of bourgeois dominance and by suspicion of ‘betrayal’. Paradoxically it was often the aristocracy that provided legislative support for the working-classes against opposition from manufacturers and industrialists.
The middle-classes of the mid-nineteenth century were an extremely heterogeneous body embracing at one end bankers and large industrialists with incomes from investment and profits of over £1,000 per year and at the other end small shopkeepers and clerks with annual earnings of under £50. The middle-classes can be divided into two broad groupings. The upper middle-class was divided into two fairly distinct groups: the financiers and merchants of London and the manufacturers of the North and Midlands. The former were generally wealthier, of higher social status and closer to the landed elites than the industrialists. 
John Leach, 1852
London bankers and City merchants were among the wealthiest people in the country. Most of the largest fortunes, such as those of the Rothschilds, Morrisons, Barings or Sassoons, came from commerce or finance and not from manufacturing and industry.  The latter were dominated by the provincial elites, those men and families controlling the growing industrial complex. Factory owners were usually wealthy but not immensely wealthy. By 1880, and perhaps earlier, Britain was as much the ‘Clearing House of the World’ as the ‘Workshop of the World’.
A lower middle-class emerged in the first half of the century and consisted of three main groups: first, smaller manufacturers, shopkeepers, dealers, milliners, tailors, local brewers; secondly, the rapidly expanding ubiquitous ‘clerk’ in both business and government; and finally, the growing professionals, schoolteachers, railway officials, an emergent managerial class, accountants, pharmacists and engineers.  Middle-class ‘occupations’ grew from 6.5% of the working population in 1851 to 7.8% by 1871. Structural changes towards a larger service sector in the late-Victorian economy resulted in a growth in the number of clerical and administrative employees.
Celebratory Dinner at Assembly Rooms, c1900, Bedale Museum
Aware of their ‘caste’, they maintained an important distinction between themselves as salaried or fee-earning employees and wage-earning manual workers. Dorothy Marshall argues that
Some of these employments were lucrative, some poorly paid, but the men who engaged in them were united in the conviction that they were socially superior to the manual worker, however skilled. The struggling clerk, who earned less than the expert fine cotton spinner, underlined his superiority by his dress, his speech and his manners. These, and not his income, were what distinguished him from the working-class.
Little had changed when E.M. Forster wrote prosaically of Leonard Bast a clerk,
The boy, Leonard Bast, stood at the extreme verge of gentility. He was not in the abyss, but he could see it and at times people whom he knew had dropped in and counted no more. He knew that he was poor and would admit it: he would have died sooner than confess any inferiority to the rich....
While sharing the aspirations and values of the class above them, the lower middle-class was under constant pressure to differentiate itself from the working-classes whose ways of life they rejected. There was an unresolved tension between the need to maintain the symbols of status and the constraints of economic reality.
There was an obsession with religious certainty, moral zeal and purity and respectability but above all keeping up appearances at all costs throughout the middle-classes and this led the children and grandchildren of the late Victorians to accuse them of hypocrisy. But this was not the only or perhaps the most abiding character trait of the middle-classes.
A person of the middle class appreciates the value of the position he occupies; and he will not marry, if marriage will so impoverish him as to render it necessary to resign his social position.
 James, Lawrence, The middle class: a history, (Little, Brown), 2006 is a detailed study. Wahrman, Dror, Imagining the Middle Class. The Political Representation of Class in Britain c.1780-1840, (Cambridge University Press), 1995 analyses the emergence of middle-class consciousness. Nossiter, T.J., Influence, Opinion and Political Idioms in Reformed England: Case Studies from the North-East 1832-1874, (Harvester), 1975 and Crossick, G. and Hauge, H.G., Shopkeepers and Master Artisans in Nineteenth-Century Europe, (Methuen), 1984 contain some useful comments on the ‘shopocracy’. Vincent, J.R., Pollbooks: How Victorians Voted, (Cambridge University Press), 1968 is a valuable examination of a major source of middle class political strength and much else. Ibid, Bourne, J.M., Patronage and Society in Nineteenth Century England is excellent for the changing notion of ‘patronage’ and its effects on the middle classes. Crossick, G., (ed.), The Lower Middle Class in Britain 1870-1914, (Croom Helm), 1977 is the most useful collection of papers and Anderson, G., Victorian Clerks, (Manchester University Press), 1976 deals with one occupational group. See also, Searle, G.R., Entrepreneurial Politics in Mid-Victorian Britain, (Oxford University Press), 1993 and Morality and the Market in Victorian England, (Oxford University Press), 1998.
 Clark, G. Kitson, The Making of Victorian England, (Methuen), 1965, p. 96.
 Clark, J.C.D., English Society 1688-1832, (Cambridge University Press), 1985, p. 71; see also his The Language of Liberty 1660-1832, (Cambridge University Press), 1993.
 This can best be seen in the agitation between 1830 and 1832 that led to the Reform Act. Those sections of the working-class that had supported reform got little or nothing. This led to a powerful sense of betrayal that fed into the demands of the Chartists for universal suffrage.
 See, Nenadic, S., ‘Businessmen, the urban middle classes, and the “dominance” of manufacturers in 19th century Britain’, Economic History Review, Vol. 44, (1991), pp. 66-85.
 On banking and the middle-class see, Cassis, Y., ‘Bankers and English society in the late 19th century’ Economic History Review, Vol. 38, (1985), pp. 210-229 and City bankers, 1890-1914, (Cambridge University Press), 1994, 2009. See also, Camplin, Jamie, The rise of the plutocrats: wealth and power in Edwardian England, (Constable), 1978.
 Crouzet, François, The First Industrialists: The Problem of Origins, (Cambridge University Press), 1985, 2008, pp. 99-115, Howe, A., The Cotton Masters 1830-1860, (Oxford University Press), 1984, pp. 50-89.
 Crossick, G., ‘The Emergence of the Lower Middle Class in Britain: a discussion’, in ibid, Crossick, G., (ed.), The lower middle class in Britain, 1870-1914, pp. 11-60; Savage, Michael, ‘Career mobility and class formation: British banking workers and the lower middle classes’, in ibid, Miles, Andrew and Vincent, David, (eds.), Building European society: occupational change and social mobility in Europe, 1840-1940, (Manchester University Press), pp. 196-216.
 Anderson, G.I., ‘The Social Economy of Late-Victorian Clerks’, in ibid, Crossick, G., (ed.), The lower middle class in Britain, 1870-1914, pp. 113-133.
 Marshall, D., Industrial England 1776-1851, (Routledge), 1973, p. 96.
 Forster, E.M., Howards End, 1910, (Forgotten Books), 1958, p. 42.
 Hammerton, A. James, ‘The English weakness? Gender, satire and “moral manliness” in the lower middle class, 1870-1920’, in Kidd, Alan J. and Nicholls, David, (eds.), Gender, civic culture, and consumerism: middle-class identity in Britain, 1800-1940, (Manchester University Press), 1999, pp. 164-182 and ‘Pooterism or partnership?: marriage and masculine identity in the lower middle class, 1870-1920’, Journal of British Studies, Vol. 38, (1999), pp. 291-321.
 Bailey, Peter, ‘White collars, gray lives?: the lower middle class revisited’, Journal of British Studies, Vol. 38, (1999), pp. 273-290.
 Fawcett, Henry, The Economic Position of the British labourer, (Macmillan & Co), 1865, p. 44.