Iliff, William Angus Boyd (1898–1972), civil servant and administrator, was born 2 October 1898 in Kircubbin, Co. Down, son of John Boyd Iliff, local merchant, and Emily Iliff (née Browne). He was educated at Mountjoy School, Dublin, before attending the Cadet College, Wellington, India. He was then commissioned in the Indian army, serving on the north-west frontier, Mesopotamia, north Persia, and south Russia. In 1922 he returned to Northern Ireland to take up a post in the newly established civil service, becoming private secretary to John M. Andrews (qv), who had been appointed as minister of labour. Later in 1935 he joined the staff of the Ministry of Labour as assistant secretary. His career within the civil service was, however, interrupted with the outbreak of the second world war, and as a major in the Supplementary Reserve Royal Artillery, he saw active service in France, particularly around Dunkirk, in the summer of 1940. On his return to Belfast he was appointed permanent secretary to the Ministry of Public Security for Northern Ireland, serving (1940–41) under the minister, John Clarke MacDermott (qv). The prime minister, Lord Craigavon (qv), had established this department in the face of mounting criticism, from unionist backbench MPs as well as public opinion at large, over the failure of his government to make a proper contribution to the war effort as well as its apparent inability to make adequate preparations against aerial attack. Among the tasks given to Iliff by MacDermott was to draw up a scheme, the ‘Hiram plan’, to allow for an advanced government headquarters to function in Belfast in the wake of a major air raid on the city. This proposed the creation of a government secretariat with the authority to act on the government's behalf in the event of communications in Belfast breaking down. Although the Hiram plan was never activated as such, the attacks on Belfast that had long been feared finally took place in April and May 1941. With the city still largely defenceless and ill prepared to cope, the result was devastating, with around 1,100 killed and some 56,000 houses destroyed.
Although no direct blame was attributed to Iliff, he was transferred out of Northern Ireland and acted (1941–4) as financial counsellor at the British legation in Tehran, Persia, and financial adviser to the governor of Burma. Then (1944–8) he was chief representative of the United Kingdom treasury in the Middle East, dealing with complex financial problems as well as the economic difficulties of newly independent states such as Iraq and Egypt. His abilities in this field were recognised in 1948 when he was appointed loan director of the International Bank for Reconstruction and Development (World Bank), and in 1951 he became assistant to its president before serving (1956–62) as vice-president. During this period Iliff's skills were employed in various capacities on behalf of the bank, most notably in the negotiations between India and Pakistan (1954–60) leading to the Indus Waters treaty (1960). In addition he acted (1958) as the bank's chief mediator in the successful discussions between Egypt and the Suez canal company to fix the level of compensation to be paid for the nationalisation of the Suez canal. His attributes as a conciliator were also applied in the context of Ireland, where in an indirect manner he encouraged the growing rapprochement between the governments in Belfast and Dublin in the 1960s. This was done by way of his decision at meetings of the World Bank in the late 1950s to place T. K. Whitaker, secretary of the Irish Department of Finance and (like Iliff) a native of Co. Down, beside the Northern Ireland delegation led by the minister of finance, Capt. Terence O'Neill (qv). Over time a relationship began to develop between the delegates from the Republic and Northern Ireland, and this was later crucial when O'Neill as prime minister sought to use the contacts built up with Whitaker as a means to open links with his counterpart in Dublin, Seán Lemass (qv).
Iliff's work was recognised with an MBE (1924), CMG (1944), and knighthood (1961). He married (1947) Jacqueline Lois Christine Reepmaker-d'Orville; they had one son. After a brief illness he died at his home near Stourton, Wiltshire, England, on 29 December 1972; his wife and son survived him.