Ash is the Head of the Influenza and Newcastle Disease workgroup at the Animal and Plant Health Agency (APHA), leading a series of teams in a diverse range of activities. He is also the Head of the National Reference Laboratory and the Deputy Director of the WOAH/FAO International Reference Laboratory for Animal Influenza and Newcastle Disease. As well as the frontline diagnosis of notifiable avian and mammalian influenza viruses and Newcastle disease, the workgroup is supported by active research programmes across a broad range of research areas. To date, Ash has published over 150 peer-reviewed articles, both in the field of avian virology as well as in the lyssavirus and morbillivirus areas where he also has considerable expertise.