Prof. Simon graduated from Oxford University. After undertaking the Fellowship of the Royal College of Surgeons (FRCS) exams, he undertook specialist training in surgery.

Prof. Kay trained in plastic surgery in the UK in Wexham, Birmingham, and Manchester, with secondments for specialist training in Adelaide, Australia, and Louisville, Kentucky, United States.

He then moved to Yorkshire, UK, and became a consultant, developing his experience in upper limb plastic surgery, children’s hand surgery, and microsurgery at Leeds Teaching Hospitals.

He developed a multidisciplinary hand surgery service in Leeds and a Children's Hand Surgery service that is now the largest such clinic in the UK.

Prof Kay is the Director of UK Hand Transplant Programme since 2016. He and his team carried out the UK's first-hand transplant operation in 2016.

He works in both the children’s and adult hand clinics and sees patients referred from all over the UK and Europe. The range of conditions he treats is very varied. These include adults with upper limb nerve and vascular problems. He runs an adult hand surgery outpatients clinic once a fortnight and his children’s hand surgery clinic is the largest in the UK.

He also runs a transplant hand clinic about once every two to three months and, his current research is on the clinical evaluation of transplantation.

Prof. Kay has also spent twenty years as an honorary visiting professor at Umea University in Sweden, which he visits two or three times a year. He also edits a textbook on plastic surgery and teaches postgraduate students all over the UK.

He has researched and published in children’s hand reconstruction, brachial plexus surgery in adults and children, and nerve repair.

He co-edited the world’s major textbook in children’s hand surgery, (The Growing Hand 2000 Mosby) and is the Editor in Chief of the Oxford Textbook of Plastic Surgery (OUP 2019).

He was appointed an Officer of the Order of the British Empire (OBE) in the 2019 New Year Honours for services to Complex Reconstructive Hand Surgery including Hand Transplantation.