Dr. Rohan D'Olier Butler (1917-1996), Historical Adviser to the Secretary of State for Foreign (and later Commonwealth) Affairs from 1963 to 1982 and Fellow of All Souls, Oxford from 1938 to 1984, was described on his death as 'a magisterial figure of penetrating intellect'. His scholarly endeavours in the field of 18th century French history culminated in 1980 with the publication of his monumental work Choiseul: Father and Son 1719-1754, a study both of the early years of Louis XV's chief minister and the intellectual climate of his times. In recognition of the excellence of Choiseul, Rohan Butler was in 1982 awarded a Laureate of the Academie des Sciences Morales et Politiques in Paris – the first person outside of France to receive such an honour, and a unique distinction for a work written in English.

Appointed by the Foreign Office in 1963 as Historical Adviser (a post which had been in abeyance since 1929), Dr. Butler became Senior Editor of the Foreign Office series Documents on British Foreign Policy and was instrumental in continuing this into the post-war period as Documents on British Policy Overseas. Dr. Butler also produced a number of authoritative internal memoranda on such diverse subjects as the Relinquishment of Abadan in 1951, the status of Stettin and most significantly in the context of this history, the Katyn Massacre.

This previously unpublished memorandum was prepared in response to an upsurge in public and Parliamentary interest in Katyn during 1971 and 1972. The first draft of the memorandum, comprising some 35 paragraphs, was submitted in September 1972. But following detailed comment from other FCO experts, and in the light of the growing controversy over the Katyn Memorial project described earlier in this history, Rohan Butler revised and extended his memorandum, taking the Katyn story up to the autumn of 1972. The memorandum was finally printed for internal circulation in the Departmental Series of Eastern European and Soviet Department as DS 2/73, dated 10 April 1973. It is reproduced here in its entirety with its original footnotes and annexes.