It was always a pleasure to listen to and to work with Peter; I learned so much from him, not only of the scientific content and context, but also of how to consider and examine the question at hand, with openness and curiosity. He was a key member of the faculty when I completed the Engineering Aspects of Infection Control course, where so many of us would have spent time with him. On this residential course there was considerable time between learning sessions, and one evening, which I believe had become traditional, Peter would lead a walking expedition of the participants to a local ancient and treasured oak tree. I enjoyed his willingness to share this special experience, which he clearly delighted in personally, with this group of colleagues, a way of broadening the discussions beyond the professional and allowing us into his world. Later, I had several occasions on which to call on his expertise back at my workplace, and on each occasion, he listened to our work to date, the circumstances we were facing, the impact on our patients and staff, and then came to visit the setting to document the facility and the potential hazards, including with revealing photographs, probing questions and in time a detailed report setting out his thoughts and recommendations. Always these were couched in beautiful language, modest, and without criticism of practices and situations. I have long thought his shoes will be hard to fill, and I am sorry he is gone. A great loss, and I feel privileged to have met him and worked with him, even a little. Ar dheis De go raibh a anam. Rest in peace Peter.