Born in Preston, Lancashire, Robert Minnitt was privately educated. He attended Trinity College, Cambridge, intending to enter the church but changed his mind after a year and went to Liverpool to study medicine instead. Qualifying in 1915, he went into general practice and became a part time anaesthetist.  He was awarded an MD in 1925.

Minnitt was a founder member of the Liverpool Society of Anaesthetists in 1930, the first provincial society of its kind in England and became Liverpool’s first Lecturer in Anaesthesia in 1933. However, he is best remembered for the development of the Minnitt nitrous oxide and air apparatus for self-administered analgesia in childbirth. This was first used at the Liverpool Maternity Hospital in October 1933 and approved for use by unsupervised midwives in 1936. Use of the apparatus continued into the mid 1960s, when Entonox became established.

Minnitt felt unable to join the NHS in 1948 and resigned his hospital appointments but maintained a small private general practice throughout the remainder of his years. He was a member of Council of the Association of Anaesthetists (1941-1944) as well as President of the Liverpool Medical Institution in 1955.  He died aged 84.