Dubbed the King of Hearts, Sir Magdi Yacoub has performed more heart transplants than any other surgeon in the world. The Egyptian-born surgeon is a scientist, an ambassador and a gentleman - and for that, he ranks at No.55 in the Power List.

Born in Cairo in 1935, Yacoub grew up to change the face of cardiothoracic surgery. He moved to Britain in 1962, and in 1969 moved to London's Harefield Hospital. Under his leadership, the hospital became the country's top transplant centre, performing some 200 operations a year.

Outside of the operating room, Yacoub has devoted himself to research through the UK's National Heart and Lung Institute. In his time there, he has helped pioneer several transplant techniques.

In 1980, he carried out a transplant operation on Derrick Morris who, until his death in July 2005, was Europe's longest-surviving heart transplant patient. Celebrities whose lives Sir Magdi has extended include British comedian Eric Morecambe and Egyptian actor Omar Sharif.

Magdi was knighted in 1992 and retired from performing surgery at the age of 65. He briefly returned to the medical scene in 2006 to advise on removing a transplant heart from a patient whose own heart had recovered.  He also spearheaded a recruitment campaign for overseas doctors in 2002, on behalf of the UK government.