Yorkshire was of paramount importance to both Progressive parties. It was a Liberal stronghold, which had to be retained. It was also the birth-place of the ILP, and the single most important area of its activity and development. If Labour was to expand then Yorkshire was an obvious target. Moreover, extensive Liberal/Labour conflict, not Progressive agreement, always seemed a possible development. A great many Liberal leaders were ideologically and politically opposed to a Progressive Alliance. Moreover, ILP dominated organisations were equally reluctant to accept co-operation with the Liberal party. Yorkshire was a crucial test of the Liberals' viability as a party of the left, and a potentially disruptive element in the Progressive Alliance.

At the same time, however, there were forces which encouraged Progressive unity. The ILP's electoral strength ensured that in some areas at least the Liberals could protect their flanks against attacks from the left by trading seats as part of a reciprocal Progressive arrangement. Similarly, there were areas, particularly in South Yorkshire, where working-class Conservatism was strong and an alliance with Labour might facilitate victories which had previously been impossible or difficult. For Labour, a Progressive Alliance meant a parliamentary foothold, and an alliance with the unions which might help it to gradually erode Liberal support.