He is well known both in the UK and internationally for his research in financial risk management for pension plans and life insurers. His research interests have centred around the development of new models for long-term risks including yield curve modelling and pricing of long-term interest-rate derivatives. More recently he has been working on the modelling of longevity risk: how this can be modelled, measured and priced, and how it can be transferred to the financial markets. Amongst his work in this field, he has developed a number of new and innovative stochastic mortality models.
He is an active member of the UK and international actuarial profession: he qualified as a Fellow of the Faculty of Actuaries in 1993; since 1996 he has been editor of the leading international actuarial journal ASTIN Bulletin - The Journal of the International Actuarial Association and has been editor-in-chief since 2005; and in 2005 he was elected as a corresponding member of the Swiss Association of Actuaries.
His research has received several international prizes including the Halmstad Prize in 2008, the Society of Actuaries Annual Prize in 2009 and the Robert I. Mehr Award in 2016.
In 2016 was elected as a Fellow of the Royal Society of Edinburgh, Scotland's national academy of science and letters.