Kay is Head of International Chemicals and Nanotechnology at the Department for Environment, Food and Rural Affairs (Defra). She leads on nanotechnologies in particularly on their responsible development within the UK and ensuring that there is an effective but proportionate regulatory framework. Her team works closely with other Government departments, but particularly the Department for Business Innovation and Skills BIS for nanotechnology. She was also Head of Delegation for the recent United Nations negotiations for a global legally binding treaty on mercury, the first Multilateral Environmental Agreement for ten years.

She covers other international conventions including Stockholm which deals with Persistent Organic Pollutants and SAICM (Strategic Approach to Chemicals Management). She was trained as a scientist, with a PhD from Imperial College and started her career carrying out applied research at the Central Science Laboratory before moving to Government policy in 1999. She has held a wide variety of policy posts ranging from the Common Agricultural Policy through to sustainable procurement and spent a couple of very enjoyable years at the British Embassy in Paris as a sustainable development and food safety attaché.