Alan Stevens spent his working life (35 years) at Rolls-Royce as a mathematical modeller, dealing mainly with design, safety and performance calculations for nuclear reactors. Rolls-Royce designs and manufactures the nuclear reactors that power the Royal Navy’s submarines. This included engineering heat transfer and fluid flow, reactor physics and whole plant modelling. In retirement he has sat on several committees of the Institute of Mathematics and Its Applications (IMA) in the UK, including its Executive Board and governing Council. He spent four years as its VP of Communications.