Mr Slesser qualified from Barts and The London School of Medicine in 2003 and is an experienced surgeon who is fully trained in all minimally invasive techniques. Slesser undertook his higher surgical training in West London. During his training, he mainly focused on honing his skills in gastrointestinal surgery. He regularly performs colorectal cancer surgery and has an interest in abdominal wall reconstruction. Mr Slesser also undertakes emergency general surgery and performs all hernia repairs as well as surgery for gallstone disease.

Mr Slesser was awarded an MSc in Surgical Sciences by Imperial College London in 2009. In 2016, for his research focused on metastatic colorectal cancer based at the Royal Marsden Hospital he was awarded a Doctorate by Imperial College London. He is a honorary clinical senior lecturer at Imperial College, London.