After completing his biblical commentary in 1951, and in addition to his headmaster's duties, Orchard embarked with
Reginald C. Fuller, his erstwhile fellow Ealing Priory pupil, on producing a new translation of the Bible, suitable for both
liturgical and academic use, which was published in 1967. Aged 60, free from stewardship of the school, Orchard resumed his career as a
biblical scholar in earnest. He participated in the establishment in 1969 and was the second General Secretary (1970–1972) of the
World Catholic Federation and, displaying the same vigour evident in his revival of St Benedict's School, organised and financed a series of international conferences on the Gospels. During the 1970s he spent four years as spiritual director of the
Beda College in Rome and took up the position of visiting
professor of New Testament Studies at the
University of Dallas (in
Dallas, Texas) before returning to Ealing for the remainder of his life. Following in the footsteps of his mentor Christopher Butler, Orchard promoted, in the face of general scholarly scepticism, the
Griesbach hypothesis, which he renamed the Two-Gospel Hypothesis. This maintained that the
Gospel of Matthew was the first and the
Gospel of Mark the third, being a synthesis of Matthew's Gospel and the
Gospel of Luke. Into his old age he remained a familiar face in biblical circles, lecturing worldwide in support of his hypothesis. Aged 95, he publicly declined the invitation of
Cormac Murphy-O'Connor, the
Archbishop of Westminster to attend a lecture which would support the priority of Mark's Gospel. Orchard's researches and ideas, regarding the Gospels, have been saved on www.churchinhistory.org ==Death==