Dr Chatterton trained as a Home Office forensic toxicologist whilst employed by the Forensic Science Service. During this time he gained approval as an Authorised Analyst from the Home Secretary and was registered with, and as assessor for the Council of Registered Forensic Practitioners (CRFP). During his time at the Forensic Science Service, Dr Chatterton managed the national drink/drug-driving unit, which processed in excess of 15,000 case samples per year.

In November 2009 Dr Chatterton took up the role of Consultant Toxicologist / Business Development Manager UK and Ireland for Eurofins Forensic Services, where he provided forensic toxicology consultancy and analytical services to a wide range of customers including HM Coroners, legal professionals, police forces, The Forensic Science Service, LGC Forensics and Forensic Science Northern Ireland.

Dr Chatterton has considerable experience in high profile criminal toxicology casework and was the lead toxicologist in the Shannon Matthews and John Worboys investigations, where hair analysis and interpretation played a critical role in successful prosecutions.

Dr Chatterton was appointed an external examiner at Bournemouth University [BSc (Hons) Forensic and Biological Sciences] in 2010. He has presented aspects of his work internationally and is a member of numerous professional organisations/societies including: The Society of Forensic Toxicologists (SOFT), The International Association of Forensic Toxicologists (TIAFT), The Society of Hair Testing (SOFT) and The Royal Society of Chemistry (RSC -CChem).  

Dr Chatterton is a fellow of the American Board of Forensic Toxicologists (F-ABFT)