Together with the suspicions he had started to harbour that a socialist government might misuse ecclesiastical patronage, the Prayer Book debacle turned Henson from a strong proponent of establishment to its best-known critic. He spent much time and energy fruitlessly campaigning for disestablishment. He was, as he had often been earlier in his career, an isolated figure. Few of his colleagues agreed with him, even those dismayed by the parliamentary vote. He was less isolated in some other causes he took up in the 1920s and 30s. He was one of many wary of the ultra-liberalism of the Modern Churchmen's Union. In 1934, he was among the senior clerics who censured Dean Dwelly for inviting a Unitarian to preach in Liverpool Cathedral and Bishop David for permitting it. He was critical of American evangelism as practised by Frank Buchman and the Oxford Group. Henson wrote of Buchman's "oracular despotism" and "the trail of moral and intellectual wrecks which its progress leaves behind."