Professor Siwan Thomas-Gibson is a leading expert in gastrointestinal medicine, specialising in high-quality colonoscopy procedures and early colorectal neoplasia management. She has been accredited as a bowel cancer screening colonoscopist since 2007, consistently prioritising patient care.

Professor Thomas-Gibson's expertise spans a wide range of gastrointestinal conditions, including inflammatory bowel disease, irritable bowel syndrome, indigestion, and post-cancer treatment bowel symptoms. She employs evidence-based approaches to both diagnosis and treatment, ensuring the highest standards of medical care.

In 2018, she was honoured with the prestigious British Society of Gastroenterology Hopkins prize, recognising her contributions to the field. Professor Thomas-Gibson has led numerous initiatives aimed at enhancing safety and standards in endoscopy, reflecting her commitment to improving patient outcomes.

An esteemed educator, Professor Thomas-Gibson frequently shares her knowledge on national and international platforms. In 2020, she was appointed as a Chair at Imperial College London, where she continues to make significant contributions to gastroenterological care, research, and education.

Her roles include not only clinical practice but also active involvement in research and teaching, making her a pivotal figure in the advancement of gastrointestinal medicine. Professor Thomas-Gibson's dedication to her field and her patients underscores her reputation as a leading specialist in gastrointestinal health.