Born in Liverpool, he studied Natural Sciences at Cambridge University, and qualified in medicine at St. Bartholomew’s Hospital, London, in 1900. He returned to Cambridge to study physiology and particularly the biochemistry of muscle contraction, research that led to his election as F.R.S. in 1915. The vision and drive of Sir Robert Morant ensured the establishment of a Medical Research Fund under the National Insurance Act of 1911, and resulted in the setting up of the Medical Research Committee to administer it in 1913; Fletcher was appointed its first secretary,  and worked closely with Morant to secure a firm foundation for future medical research. He was knighted in 1918 in recognition of his services during WW1 after which he worked to secure the transition from Medical Research Committee to MRC, set up by Royal Charter under the Privy Council in 1920, and guaranteed independence from any government department. He remained first secretary of MRC for 20 years until 1933, a period during which he was enormously influential in establishing a secure base for medical research in UK, and also in India. There was a very close personal relationship between Fletcher and Greenwood recalled by Higgs [10]. The two had disagreed in 1931 about the role of the Ministry of Health in disseminating new information on nutrition collected by MRC. After they fell out, Greenwood wrote "I really care but little for intellectual rights and wrongs, outside of working hours. I care a great deal for human friendship at all hours. I am very sorry I hurt you"; Fletcher replied saying that Greenwood’s arguments would have "made me cross if I did not love you so much". 

Correspondence with Professor AV Hill the Nobel Prize Winner are in Churchill College Cambridge.

Sketch by him of his wife’s aunt Margaret Jones (nee Cropper) is in Trinity College Cambfridge archives

Subject of the book “The Bright Countenance” by his wife Maisie.

See Dictionary of National Biography.