He is lately Consultant Pharmacist & Director of Legal Services and formerly Director of Pharmacy Services for the University Hospitals Bristol NHS Foundation Trust based at the Bristol Royal Infirmary. He is also principal in the firm of Harrowing & Warwick, Consulting Pharmacists, of Bath.

His qualifications are Bachelor of Arts (BA (Hons.) (Philosophy), Bachelor of Pharmacy (BPharm (Hons)), Bachelor of Laws (LLB (Hons.)), Master of Laws in Medical Law and Practice (LLM) and He has a Post-Graduate Diploma in Legal Practice. He has a Doctorate in Pharmacology (PhD) and his professional qualifications are Chartered Scientist (CSci); Chartered Chemist (EurChem,CChem,MRSC); Chartered Biologist (CBiol,MSB); Fellow of the Chartered Quality Institute (FCQI, CQP); Member of the College of Pharmacy Practice (MCPP) and Registered Pharmacist (MRPharmS). He is a Member of the Academy of Experts, British Academy of Forensic Sciences and the Forensic Science Society.

He has thirty three years experience as a hospital and community pharmacist and has particular expertise in prescribing, pharmacology and therapeutics as well as side-effects and adverse drug reactions. He has published papers on aspects of pharmacology and the use of hazardous substances. He was formerly an examiner in post-graduate clinical pharmacy for the University of Bath and has considerable experience in the preparation of medico-legal reports in clinical negligence and medical negligence matters, as well as criminal and professional disciplinary proceedings, involving drugs and medicines.