Mr. Diab is a consultant Obstetrician and Gynaecologist with expertise in problems that occur during early pregnancy, such as recurrent miscarriages and ectopic pregnancy, as well as pelvic pain, acute gynaecology, fibroids, subfertility, endometriosis, and abnormal uterine bleeding.

He obtained his medical degree in 1984 from Ain Shams University Hospitals in Cairo, Egypt, and completed his basic specialist training in Obstetrics and Gynaecology there. After moving to the UK in 1998, he underwent further specialist training in the South East Thames Region, including working as a Senior Registrar, Senior Clinical Fellow, and Locum Consultant at Guy's and St Thomas' Hospital for four years. He has also obtained advanced training and accreditation in performing laparoscopic surgery, hysteroscopic surgery, and gynaecological ultrasound.

From May 2009 to September 2014, Mr. Diab was a consultant Obstetrician and Gynaecologist at the Royal Surrey County Hospital NHS Foundation Trust, where he served as clinical lead for emergency gynaecology and early pregnancy services and was the lead consultant for medical education. Since September 2014, he has been appointed at Guys and St Thomas' NHS Foundation Trust as a consultant gynaecologist with a special interest in early pregnancy and acute gynaecology, during which he held the positions of lead clinician for emergency gynaecology and lead clinician for undergraduate medical education. He currently serves as the head of service for gynaecology.

As a senior gynaecologist, Mr. Diab mentors and supervises junior consultants and performs complex open and keyhole gynaecological procedures. He has a special research interest and has published papers in the field of gynaecological surgery.