With Sir Arthur Ellis of the London Hospital Medical College, he worked on Bright's disease and on the relationship between nephritis (inflammation of the kidneys) and hypertension (high blood pressure).

[7] By the age of 18 years, he decided on a career in medicine, and with a science scholarship,[8] studied at the London Hospital medical college from 1921 to 1928.

[9] Becoming assistant to the medical unit at the London Hospital by 1929, Evans developed a close connection with Sir Arthur Ellis and Clifford Wilson.

[8] He then gained a wide range of clinical experience by taking up posts in surgery, obstetrics, anaesthetics and pathology.

He was later physician to her son, King George VI from 1949, receiving a knighthood (Knight Commander of the Royal Victorian Order) in the same year.

[10] Evans was part of the team that looked after King George VI during his ill health with lung problems and up until his death.

Frequent attacks of pain requiring strong painkillers and periods of rest prompted more extensive investigations.

It is agreed that the initial operation resulted in biliary tract damage, a complication well recognised at the time, and much corrective surgery was needed later by Richard Cattell, again a recommendation of Evans.

That the surgery should be done in the United States was objected to by Winston Churchill, who felt that if the king had his operation on a "kitchen table'," Eden could at least have his in a London hospital, but Evans and Cattell visited them at 10 Downing Street and agreed the transfer abroad.

On Eden's visit to New Zealand in 1957, Evans made notes for doctors should he require medical assistance whilst abroad:[11] His general health during the past year has been maintained with extensive vitamin therapy—sodium amytal gr 3 and seconal enseal gr 1.5 every night and often a tablet of Drinamyl every morning.

Towering and marginally slouched, he wore horn-rimmed glasses and enthused confidence in those who sought his advice, whether patient or colleague.