In 1966, after bouts of malaria, Hastings returned to England and became active in ecumenical dialogue through the preparatory commission of the Anglican-Roman Catholic International Commission. He was also commissioned by a number of Anglican dioceses in Africa to prepare a report on Christian and customary marriage. From 1972 to 1976 Hastings was on the staff of an ecumenical missionary school, the College of the Ascension in Selly Oak, Birmingham. In 1973 Hastings brought the massacres carried out by the Portuguese army during the Mozambican War of Independence to world attention, first in "The Times" and later at the United Nations. He created a controversy in 1973 with an article in "The Times" about the "Wiriyamu Massacre", in the Portuguese-ruled overseas territory of Mozambique, revealing that the Portuguese army had massacred some 400 villagers at the village of Wiriyamu, near Tete, in December 1972. His report was printed a week before the Portuguese prime minister, Marcelo Caetano, was due to visit Britain to celebrate the 600th anniversary of the Anglo-Portuguese alliance.