Over the course of his career in far-right politics, Tyndall became less outspoken on race after his prosecution under the race relations legislation. In the mid-1970s, Tyndall used "Spearhead" to claim that "the negro has a smaller brain and a much less complex cerebral structure" than white Europeans. In 1988, Tyndall described his crime as having "dared to publish an honest and frank opinion on the relative merits of Whites and Negroes." Tyndall argued that non-whites were unassimilable to Britain and that those living in Britain should be repatriated. Tyndall strongly objected to interracial relationships and miscegenation and remarked in his book "The Eleventh Hour": "I feel deeply sorry for the child of a mixed marriage, but I can have no sympathy whatever for the parents ... They produced an offspring that will never wholly fit, and will undoubtedly face a life much harder than the normal person born of pure race." In contrast to his views on non-white migration, he spoke positively of white immigrants from Ireland, Poland, Hungary, and the Baltic states, regarding them as being racially similar and sharing the "same basic culture" as the British and were thus easily able to assimilate "within a generation or two".