Over a year after he assumed the leadership, at a party meeting on 20 September 1955, senior party member Ken McCaw moved that the leadership be declared vacant, citing that Robson's leadership lacked the qualities necessary for winning the next election. The motion was carried 15 votes to 5. Robson then moved a motion to prevent Pat Morton, who was the only person nominated for leader, from taking the leadership. This was defeated 16 votes to 6 and Morton was elected unopposed as leader, with Robert Askin remaining as Deputy Leader. Robson retorted that there had been a "continuous intrigue" against his leadership. He was returned for the last time at the 3 March 1956 election with 71.41%. Robson, however, did not stay long afterward; on 26 July 1957, he resigned his seat, and returned to his legal practice until he retired.