Paul Shanahan was at the heart of reforms in global agricultural trade law and policy over the past four decades. These included the crucial Uruguay Round trade negotiations, whose successful conclusion led to the establishment of the World Trade Organisation that proved to be a catalyst in the growth of global agricultural trade.

Shanahan worked for more than 25 years as a senior counsellor and director in the Agriculture & Commodities Division of the World Trade Organisation (WTO) and in the secretariat of its predecessor, the General Agreement on Tariffs and Trade (GATT). As a senior GATT official he played a crucial role in the preparatory work for the Uruguay Round Agreement on Agriculture and, as secretary to the Negotiating Group on Agriculture from its creation in 1986 until the completion of the negotiations, was instrumental in the creation of the legal agreement. During the delicate and complex discussions on agriculture, it was up to the chairman, at that time Aart de Zeeuw of the Netherlands, and Shanahan as secretary, to bridge the differences in members' negotiating positions and find the necessary compromises. Much of the final legal agreement was drafted by Shanahan himself.

The Uruguay Round Agreement changed the way in which governments around the world supported their agricultural sectors and how products are traded. It set the stage for the elimination of export subsidies for agricultural products, removed quotas on agricultural imports and established rules on what governments could do to bolster their agricultural sector, thus removing trade barriers. There had been numerous efforts made over the years to develop specific trade rules for agricultural products, but no firm agreement was reached until 1994.

Shanahan also assisted WTO dispute resolution panels to make rulings in a number of landmark cases relating to agricultural trade. His written opinions informed the outcome of cases such as the US complaint over the EC oilseed regime, and the Brazil complaint about US cotton subsidies.

In the 1992 oilseed dispute, Shanahan served as secretary to the panel. His opinion, which was drafted on behalf of the GATT panel, was delivered in the face of considerable internal and external political pressure to take a pro-EC stance. This was a landmark agricultural case, with retaliation valued at over $2 billion, and it played out during the Uruguay Round negotiations. Shanahan's characteristic analysis was sound and compelling, and the panel ruling based on that analysis required unprecedented changes in EC policy. The panel finding and initial steps in EC oilseed policy reform ushered in subsequent, broader reforms; thereby allowing the Uruguay Round to conclude.

Shanahan was born in New Zealand in 1942, the son of a New Zealand statesman, Foss Shanahan, who served his country as, among other things, Secretary of the Cabinet and New Zealand War Council, Ambassador to Thailand, High Commissioner to the Federation of Malaya, Permanent Representative to the United Nations, High Commissioner to Canada and President of the United Nations Economic and Social Council.

Shanahan married Helen Falvey in 1966, daughter of Sir John Falvey QC, a lawyer and minister in the Fiji government, an architect of Fiji's independence constitution, and Fiji's first Attorney General from 1970 to 1977.

Having read law at Victoria University, New Zealand, Shanahan was admitted as a barrister and solicitor in 1972. He started his career with the New Zealand Treasury's economic and legal divisions, where he specialised in external trade and trading relations, and the New Zealand Ministry of Foreign Affairs. He was New Zealand's Deputy High Commissioner and acting High Commissioner in Papua New Guinea from 1979 to 1982.

It was during his time in Papua New Guinea that Shanahan developed a friendship with Mother Teresa of Calcutta, a regular visitor to the country. On one occasion she turned up at the New Zealand High Commission unannounced, and Shanahan was told by the receptionist that there was a little barefoot nun looking for him and should she be sent away. His wife shared his friendship with Mother Teresa, donating her diamond engagement ring to help to fund Mother Teresa's mission in the remote Highlands of PNG.

As a diplomat Shanahan met many ambassadors and heads of state, and travelled regularly to discuss agricultural trade across the globe, including being invited to dine and smoke cigars with with Fidel Castro in Havana.

He retired from the WTO in September 2004. After retiring Shanahan provided a great deal of pro-bono advice on WTO matters to a number of developing countries and lectured on WTO law at several universities.

Shanahan is survived by his wife and their five children. Paul Shanahan was born on January 16, 1942. He died on October 19, 2008, aged 66