Jonathan van Dellen is a Consultant Colorectal and General Surgeon with a subspecialist interest in pelvic floor disorders such as rectal prolapse and incontinence, inflammatory bowel disease, diverticular disease and complex proctology including anal fistulas and pilonidal sinuses. His NHS practice is based at Croydon University Hospital, where he works together with the Inflammatory Bowel Disease, Pelvic Floor, Urogynaecology and Endometriosis teams. He regularly collaborates with dieticians, specialist nurses and pelvic floor physiotherapists to provide a multidisciplinary patient-centred approach. He is accredited in colonoscopy and a member of the Pelvic Floor Society, Enhanced Recovery After Surgery Society and Association of Coloproctology of UK and Ireland.

He qualified from Guy’s, King’s & St. Thomas’ Hospitals in 2006 and undertook his surgical training in London and South West Thames, followed by an advanced fellowship at Guy's and St. Thomas' Hospitals in his subspecialist areas of interest. He was awarded his doctorate from Kings College London in 2017 for research into improving patient outcomes in colorectal surgery and Enhanced Recovery After Surgery protocols. He is the Royal College of Surgeons Tutor at his NHS trust and has a keen interest in surgical education, training resident doctors and allied health professionals.