Prince William follows in his mother’s footsteps as he visits the Royal Marsden Hospital
The Duke – who had spent the morning with his wife Kate in the Capital supporting the poppy appeal – witnessed the complicated procedures in the hospital's Wolfson Surgical Suite after meeting the operating teams led by surgeons Stuart James and Pardeep Kumar. "It's slightly surreal meeting you in this situation," he said.
Both patients, a woman in her 60s undergoing breast reconstruction and a man in his 80s having the bladder tumour removed, had agreed to let the second in line to the throne sit in on their operations but did not get to meet him beforehand.
When asked how he was feeling, the hands-on royal held his stomach and replied: "Good. Still standing."
He spent around 10 minutes viewing the breast procedure, lookng into a micro-vascular microscope placed above the body, as he was talked through the surgical procedure, which usually takes six to eight hours to complete.
"That's amazing," he said as he peered through the microscope. "That's incredible. Is this fairly major surgery?"
"Think of it as long rather than major," Mr James replied.
The Duke donned a face mask as he moved into a second operating theatre to view surgery to remove a bladder tumour for a male patient in his 50s. The pioneering procedure allows the patient to retain his bladder and thus avoid having to wear a bag for the rest of his life.
"There's space for you on this side," Mr Kumar, the lead surgeon, said.
"Thank you, perfect," the Duke replied.
"Nobody fainted. The Duke was very calm, very interested in our pioneering, innovative surgery."
The 31-year-old is the first royal to view surgery at the Royal Marsden and follows in the footsteps of his mother, who watched a heart operation at Harefield hospital in Middlesex in 1996.
Speaking after his visit, a hospital spokesperson said: "Nobody fainted. The Duke was very calm, very interested in our pioneering, innovative surgery."
William has been president of the hospital trust since 2007, a position previously held by Diana from 1989 until her death in 1997.
"He is president of the Royal Marsden so he needs to know about and get to see as much of the work that goes on there as possible," a Kensington Palace spokesman said ahead of his visit.
The Wolfson Surgical Suite was reopened in 2010 following an extensive rebuilding and refurbishment programme after a fire in 2008 devastated the theatre area.
The Duke and the Duchess of Cambridge previously opened the trust's cancer unit for children and young people at its hospital in Sutton, south London, in 2011.