It was in 1872 that English agricultural labourers formed their first nationally organised trade union, and with this development came immediate pressure to secure improved wages and reduced hours of employment, wherever possible. In such circumstances unionists were clearly anxious to create a general scarcity of labour, in order to strengthen their bargaining position, and they particularly frowned upon the itinerant Irish workers who came to swell the agricultural market during the hay and corn harvests. Although, from the farmers' point of view, extra labour was clearly needed at these busy seasons of the year, the farm workers themselves were keen to eliminate—or at least to regulate—this type of competition.
In practice the Irish harvest migration had probably already reached its peak by the end of the 1840s and had then fallen off fairly rapidly, in the face of the massive emigration movement of the early 1850s.