Derek is a (recently retired) Orthopaedic Consultant Surgeon who specialised in knee surgery with senior positions in Sheffield NHS teaching hospitals. He founded One Health after leaving the NHS in 2000 in pursuit of a better way of operating through outsourcing services from the NHS. He is recognised as one of the UK's leading knee surgeons and took referrals nationally and internationally including many high-profile athletes. He held appointments as the Knee Tutor at the Royal College of Surgeons of England and served as an executive member of the British Association of Surgery of the Knee. He has also served on the board of the Journal of Bone and Joint Surgery. Derek is frequently invited to lecture on knee surgery at national and international meetings.