Despite his lack of contact with the British workers, however, Marx sensed at once, as he told Engels, that "this time real 'powers' were involved both on the London and Paris sides." For that reason alone he was ready to waive his "usual standing rule to decline any such invitations
actually, British/French unionists invited Marx to their meeting.
Karl Marx, the International and the British Trade Union Movement
pdf: https://sci-hub.se/https://www.jstor.org/stable/40400876
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