Roberts joined the Foreign and Commonwealth Office as Third Secretary in 1968. He went to study Arabic at MECAS in the Lebanon in 1969, and was posted to Paris in 1970. He was acting Head of Chancery in Luxembourg in 1973 before returning later that year to the FCO to serve firstly in Eastern European and Soviet Department, then in Western European Department and subsequently in European Integration Department, where he worked on the European Community's Common Agricultural Policy and the European Parliament. He was appointed First Secretary at the British High Commission in Canberra in 1978. In 1980 he was posted temporarily to the newly independent Pacific state of Vanuatu as Political Adviser at the time of a rebellion. He returned to Canberra as Head of the Economic and Commercial Department and Agricultural Adviser until 1982. He then returned to London and took up the post of Deputy Head of News Department in the FCO. From 1989 to 1993 he was Minister in the British Embassy in Madrid. He was appointed Chargé d'Affaires and Consul-General in Belgrade in March 1994, and after recognition of the Federal Republic of Yugoslavia by the United Kingdom, he became Ambassador. During his time at Belgrade he conducted negotiations on behalf of the international mediators with both the Yugoslav authorities and the Bosnian Serbs. Roberts was also involved in the negotiations for the release of British soldiers held hostage by the Bosnian Serbs in May/June 1995. He left Belgrade at the end of 1997. In 1998–99 he took a sabbatical year as Senior Associate Member of St Antony's College, Oxford. Roberts returned as Ambassador to Ireland 1999–2003, and to Italy from March 2003 until his retirement in 2006.
Post retirement
After Sir Ivor retired from HM Diplomatic Service in September 2006 he took up the post of President of Trinity College, Oxford. On 24 September 2006, The Observer's Pendennis column reported that, following his outspoken valedictory report, the FCO had abandoned the centuries-old tradition of allowing departing diplomats to speak their minds. In April 2007, The Independent confirmed the story. In April 2017, Roberts announced that he had taken Irish citizenship following the Brexit result. The citizenship arises from Roberts's father, who was born in Belfast.
Roberts married Elizabeth Smith, a scholar of French poetry and formerly a diplomat in the Australian Foreign Service, in 1974. Lady Roberts is a writer and lecturer on Balkan politics. The couple have two sons and a daughter.
Publications
In 2009, Roberts edited the sixth edition of Satow's Diplomatic Practice, originally written in 1917 by Sir Ernest Satow and widely used in embassies throughout the world. It was reviewed by Sir Jeremy Greenstock later the same year. The seventh centenary edition, also edited by Roberts, appeared in 2017.. His memoir of his years in the Balkans, Conversations with Milosevic, was published in 2016.
