Susan Willett: Defence expert who argued that an ethical arms policy is essential for international security

Sue Willett was an expert in the economics of defence and international defence policy. She became one of the foremost authorities on the vicious cycle of debt, underdevelopment and conflict in the developing world and called for radical action by the international community to break the cycle. Her conviction that the developed world can only bring about security if it pursues an ethical arms policy has been vindicated time and time again.

Susan Mary Willett was born in 1952 in Henley-on-Thames, though her early life was spent in colonial style in an army family in Kenya and Singapore before she joined Newton Abbot Grammar School in Devon. By her late teens she was embracing the radical ideas of the 1960s, clashing with her authoritarian father, who refused to support her through art college.

It was a conflict that launched her on an independent path and by the age of 22 she had married and had a son. She joined her husband, Fred Hasson, as an undergraduate at the School of Peace Studies at Bradford, juggling childcare, studying and playing an active part in the European Nuclear Disarmament movement. In 1980, as part of her degree, she travelled to post-revolutionary Nicaragua to work on the literacy campaign with the NGO Third World First. There, memorably, she was threatened at gunpoint in her hotel room by Maoist guerrillas.

By the time she graduated, she had discovered her talents as a researcher and writer and was excited by the chance to engage critically with Britain's role in the developing world. She took an MPhil at the Institute of Development Studies at Sussex, which launched her on an academic career as an expert on the economics of defence. Willett was a feminist and a rigorous thinker who never took orthodoxies at face value but looked for the vested interests behind every institutional policy and pronouncement. She spent two years researching at Birkbeck College, where she learnt a healthy disrespect for reductionist econometric modelling. She then took a research position at the Centre for Defence Studies at Kings College London, building her reputation over seven years as a specialist in international defence policy and development, especially in sub-Sarahan Africa.

In 1993 she was invited to help draw up the defence budget for the first ANC government-in-waiting, and was a guest at the Guild Hall dinner forNelson Mandela's first visit to the UK. She also acted as a UN election monitor in South Africa, Mozambique and Croatia. Later she spent time at the Copenhagen to the Peace Research Institute before joining the United Nations Institute for Disarmament Research in Geneva.

An articulate speaker, Willett was often asked to contribute as a defence expert to television discussions. She would calmly demolish unsubstantiated assertions from the defence establishment – often to the consternation of some of her senior colleagues. She was the first to suggest that Britain's defence budget would be better served by buying Sukoi jets from Russia at a quarter of the cost, than by proceeding with the hugely expensive Eurofighter jet. Its role, she astutely asserted, was defunct before it was built. Her study of Europe's role in the proliferation of weapons in South East Asia made her an important expert during the row over British arms sales to Indonesia.

Sue Willett was never a one dimensional academic but lived life to the full, whether in the company of friends, discussing the latest novels, or windsurfing in the English Channel or off the coast of Spain. Her good looks and radiant smile lit up every room she entered. She was an impeccable hostess and took pride in serving wonderful meals on the most tasteful tableware. Her passionate views would often keep her dinner companions up debating late into the night.

She was a prolific writer of research papers and contributed to several books on defence. Confident of her knowledge and expertise, she was comfortable moving in the very male world of military affairs – perhaps, as she often said, because she'd grown up in such a world as a child. But her familiarity with this world did not stop her being its fiercest critic. She was driven by a passionate belief that corporate vested interests were corrupting the West's foreign and defence policies, making the world a more dangerous place.

Recently, with Western defence circles increasingly caught up with the so called "war on terror", Willett's incisive analysis was less in vogue and she complained that it was harder to get her research funded by mainstream sources. She continued writing for disarmament publications, contributing regularly to the journal International Peacekeeping. In 2010 she was the guest editor of its special issue on "Women, Peace and Conflict: A Decade after Resolution 1325".

Sue Willett remained a radical to the end, perhaps unconsciously taking her cue from her Suffragette grandmother. Her talent for interior and garden design were informed by a keen artistic eye and an enquiring mind that fashioned lovely homes and beautiful gardens. She has left her mark wherever she lived – on the wild, windswept hills of the Pennines, in the West Country, in the gardens around her home in Brighton and her house in Gaucin. In the last few years she inspired many friends with her enthusiasm for yoga, training as a yoga teacher herself.

In her last year her fearsome energies were deployed in her fight to survive inoperable pancreatic cancer. She read widely on alternative treatments and, with the support of her family, established a dietary and spiritual regime of extraordinary self-discipline. That she construed her dreadful prognosis as her final adventure in life was a perfect example of the kind of indomitable fighter she would want to be remembered as. She will also be remembered as a great cook, a funny raconteur and someone not to lock horns with – unless one was well prepared for a trenchant debate.

Susan Mary Willett, defence expert: born Henley-on-Thames 3 December 1952; married 1974 Fred Hasson (one son); died Brighton 13 May 2011.