Gary works at the interface of science and policy, supporting Defra's Chief Scientific Adviser in ensuring the credibility and impact of Defra group's science and evidence. He leads on a project to increase the value form Defra group's reporting of scientific and statistical information to international bodies and is a member of Defra's International Science Network and adviser to the Systems Research Programme. Gary was previously Deputy Chief Scientist at natural England, where he championed the scientific capabilities of Natural England's staff, spanning natural and social science. Gary also provides a lead for the UK on horizon scanning and futures within the European Information and Observation Network (Eionet). Gary developed an interest in policy following his work in consultancy, and led the energy and environment programme at the Parliamentary Office of Science and Technology. He has worked extensively with the Government Chief Scientific Advisor and Science Minister to develop new policy and delivery mechanisms to strengthen the relationship between science and society, and has informed the development of the Natural Environment White Paper. He is currently on secondment as Deputy Chief Scientist at Defra. Gary is also a Visiting Professor at the Centre for Environment and Sustainability at the University of Surrey.

Gary joined the IES in 2013, became a Fellow in 2014, and joined the IES Council in the same year. "I am keen to...take an active role in driving up the standards of science and knowledge exchange in evidence-based approaches to policy and decision-making. I have a particular interest in interdisciplinary, systems-based approaches to applying science to environment and sustainability challenges and to this end... The IES can reach widely across the environmental sciences and across the academic, practitioner, policy-maker divides, helping to move environmental sciences forward and maximise the chances of achieving impact in tackling real-world issues."

Gary was elected Vice Chair in 2015 and served as Chair between 2018 and 2021.  In 2021 he was elected Vice President in recognition of his service to the IES.