Meet the JAG clinical team

If you would like to contact any of the individuals listed below, please contact the JAG office by email at

You can also read about the JAG office team here.

Dr Siwan Thomas-Gibson

Chair of the JAG

Dr Siwan Thomas-Gibson has been chair of the JAG since January 2017. She is a specialist endoscopist and luminal gastroenterologist at St Mark's Hospital, an honorary senior lecturer at Imperial College London and is director of education at St. Marks Academic Institute. In 2006 she was awarded an MD at Imperial College London for her work in ‘Improving Training and Assessment in Colonoscopy’. She has published over 60 scientific papers as well as National Guidelines and several book chapters. As chair of JAG, Siwan’s aims are to improve communication between JAG and clinical services; to develop JAG research and data output and to improve safety and learning from error within endoscopy.

 Photo of Siwan Thomas-Gibson

Dr John Green

Chair of the Endoscopy Services Quality Assurance Group (ESQAG)

Dr John Green has been the chair of ESQAG since April 2016 and is also a lead assessor on JAG accreditation assessments. He is a consultant gastroenterologist in Cardiff & Vale UHB. He is the clinical director for gastroenterology in Cardiff and is a bowel cancer screening colonoscopist. He has co-authored a text book on gastroenterology for medical students and is the year 3 director for medical undergraduates in Cardiff University.

 Photo of John Green

Dr Neil Hawkes

Chair of the Quality Assurance of Training Working Group (QATWG)

Dr Neil Hawkes is a consultant gastroenterologist at the Royal Glamorgan Hospital

 Photo of Neil Hawkes

Debbie Johnston

Head of Assessors

Debbie Johnston is the head of assessors, providing expert leadership to over 30 assessors, ensuring consistent application of the JAG standards, and assessments of the highest possible quality. She has over 30 years’ experience in healthcare in nursing, managerial, quality improvement and quality assurance roles, and has played a key role in the development of the JAG scheme since its establishment in 1994. Debbie has developed advanced skills in many areas, including: training and leadership skills development; quality improvement; assessor training and development; change management; programme and business management skills. She has a pivotal role in the ongoing development of all of the accreditation schemes hosted by the accreditation unit at the Royal College of Physicians.

 Photo of Debbie Johnston

Helen Griffiths

Deputy Head of Assessors

Helen Griffiths is a retired nurse consultant with over 25 years’ experience in gastroenterology. She continues to work part time as an endoscopist and trainer at Wye Valley NHS Trust. Her doctorate and special interest is in Barrett’s oesophagus, supporting master classes and training in this area. Appointed as deputy head assessor for JAG in 2017, she has worked as a JAG assessor and lead assessor since 2007. Helen is the decontamination advisor for the BSG and represents nurses on a number of working parties for BSG clinical guidelines and guidance documents. She lectures nationally and internationally in gastroenterology and advanced nursing practice, and represents the profession and specialty on a number of medical and nursing committees.

 Photo of Helen Griffiths

Dr Brian McKaig

Chair of Bowel Cancer Screening Programme (BCSP) Accreditation Panel

Dr Brian McKaig is the chair of the BCSP Accreditation Panel, having been a bowel cancer screening colonoscopist and assessor for over 10 years. He represents the BSG on the National Advisory Committee for Bowel Cancer Screening and is the professional clinical advisor (colonoscopy) for the West Midlands Bowel Cancer Screening QA service. He is co-director of the West Midlands Regional Endoscopy Training Centre and have an active role in the JAG developing training pathways as part of the JAG QA of Training Working Group. Brian is associate medical director for Royal Wolverhampton NHS Trust with a lead role in consultant appraisal, revalidation and job planning and has a specialist interest in advanced colonoscopy and endoscopy training.

Photo of Brian McKaig

Professor Matt Rutter

Chair of the National Endoscopy Database (NED) working group

Professor Matt Rutter is professor of gastroenterology at Durham University, specialising in advanced diagnostic colonoscopy, polypectomy and IBD. Matt leads the group developing the National Endoscopy Database (NED)

 Photo of Matt Rutter

Dr James East

Chair of the JAG research committee

Dr James East is a  gastroenterology and clinical lead at Oxford University Hospitals and is also the Director for the Oxfordshire Bowel Cancer Screening programme.

 James joins JAG to chair the new JAG research committee.



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