Engels, in his writings on the English working class from the 1840s, evinced considerable enthusiasm over the growth of strike struggles and trade unions. But even at this early stage, he criticized the narrowness of the unions and considered Chartism to be a superior and more advanced form of struggle. In his later writings, he associated the rise of the unions with a political decline in the labor movement, following the breakup of the Chartist movement after 1848. He became increasingly contemptuous of the unions, describing their transformation from instruments of working class insurgency into well-established institutions of the official status quo.
In an 1879 letter to Bernstein, Engels did not mince words as to the state of the English labor movement:
“For a number of years past the English working-class movement has been hopelessly describing a narrow circle of strikes for higher wages and shorter hours, not, however, as an expedient or means of propaganda and organization but as the ultimate aim. The Trades Unions even bar all political action on principle and in their charters, and thereby also ban participation in any general activity of the working class as a class...
“One can speak here of a labour movement only in so far as strikes take place here which, whether they are won or not, do not get the movement one step further. To inflate such strikes—which often enough have been brought about purposely during the last few years of bad business by the capitalists to have a pretext for closing down their factories and mills, strikes in which the working-class movement does not make the slightest headway—into struggles of world importance, as is done, for instance, in the Freiheit, published here, can, in my opinion, only do harm. No attempt should be made to conceal the fact that at present no real labour movement in the Continental sense exists here, and I therefore believe you will not lose much if for the time being you do not receive any reports on the doings of the Trades Unions here.” 
In 1881 he wrote: “Trades Unions have now become acknowledged institutions, and their action as one of the regulators of wages is recognized quite as much as the action of the Factories and Workshops Acts as regulators of hours of work.” 
In the same article he anticipated the emergence of new, political forms of struggle that would overcome the stifling influence of the unions on the working class:
“More than this, there are plenty of symptoms that the working class of this country is awakening to the consciousness that it has for some time been moving in the wrong groove; that the present movements for higher wages and shorter hours exclusively, keep it in a vicious circle out of which there is no issue; that it is not the lowness of wages which forms the fundamental evil, but the wages system itself. This knowledge, once generally spread amongst the working class, the position of the Trades Unions must change considerably. They will no longer enjoy the privilege of being the only organizations of the working class. At the side of, or above, the Unions of special trades there must spring up a general Union, a political organization of the working class as a whole.” 
In a famous article entitled “England in 1845 and 1885,” Engels described the shift in the attitude of the manufacturing bourgeoisie toward the unions following the rapid growth of British industry in the decades that followed the repeal of the Corn Laws (1846):
“Thus a gradual change came over the relations between both classes. The Factory Acts, once the bugbear of all manufacturers, were not only willingly submitted to, but their expansion into acts regulating almost all trades, was tolerated. Trades Unions, lately considered inventions of the devil himself, were now petted and patronized as perfectly legitimate institutions and as useful means of spreading sound economic doctrines amongst the workers. Even strikes, than which nothing had been more nefarious up to 1848, were now gradually found out to be occasionally very useful, especially when provoked by the masters themselves, at their own time.” 
Of the “great Trades Unions,” he wrote: “They form an aristocracy among the working class; they have succeeded in enforcing for themselves a relatively comfortable position, and they accept it as final. They are the model working men of Messrs. Leone Levi and Giffen, and they are very nice people indeed nowadays to deal with, for any sensible capitalist in particular and for the whole capitalist class in general.
“But as to the great mass of the working people, the state of misery and insecurity in which they live now is as low as ever, if not lower.” 
As for the relations between the First International and the trade unions, they were, contrary to Spartacists’ depiction, essentially antagonistic. In a letter of 1871 to Carlo Cafiero, an Italian socialist who helped organize a section of the International in Naples, Engels wrote, “The trade-union movement, among all the big, strong and rich trade unions, has become more an obstacle to the general movement than an instrument of its progress...” 
In a letter of 1887 to John Mahon, a Scottish socialist, he said, “What you say about the leaders of the Trades Unions is quite true. We have had to fight them from the beginning of the International. From them have sprung the Macdonalds, Burts, Cremers and Howells, and their success in the parliamentary line encourages the minor leaders to imitate their conduct.” 
During the life of the First International, Marx paid considerable attention to the development of trade union and strike struggles, and he held open the possibility that the unions could contribute to the revolutionary liberation of the working class. However, he had no illusions that they could serve as a substitute for the independent political organization of the working class. Thus, for example, at the Basle conference of the International, Marx spoke in opposition to a resolution submitted by a French delegate proposing the establishment of an international federation of trade unions. Such an association, the delegate declared, would be “the true commune of the future.”
According to a report of Marx’s speech, “He [Marx] denies that it is the commune of the future because [this] project rest on the division of labor, principal cause of the slavery of the workers. It may ameliorate the lot of the workers a little, but it cannot be offered as an ideal.” 
Another report quotes Marx as follows: “The trade unions by standing alone are powerless—they will remain a minority. They do not have the mass of proletarians behind them, while the International influences these people directly; the International doesn’t need the organization of trade unions in order to win the workers—the ideas of the International inspire them at once. It is the only union which inspires full confidence among the workers.” 
In the final years of his life, Engels hoped that the emergence of unions among the more oppressed sections of workers, particularly the impoverished laborers of London’s East End, and struggles such as the great dock workers’ strike of 1889, signaled a new, militant brand of trade unionism that would contribute to the development of a mass socialist movement of British workers. Marx’s daughter, Eleanor, played a leading role in the early struggles of one of these unions, the gas workers, as well as the political agitation that led to the formation of the Labour Party. But by the time of his death in 1895, Engels was writing with bitterness of the inclination of the leaders of the “new unionism” to follow the same conservative path as their predecessors.