Born in London in 1915, he was the second son of Sir Alan Barlow, son of Thomas Barlow, royal physician. His mother was Lady Nora Barlow, daughter of Sir Horace Darwin. He was a great-grandson of the naturalist Charles Darwin. He was named after his great-great-great-grandfather Erasmus Darwin. His elder brother was Commodore Sir Thomas Erasmus Barlow, a younger brother is Horace Barlow.

He was educated at Marlborough College, and Trinity College, Cambridge, where he studied medicine. He also studied at University College London.

He married Brigit Ursula Hope Black (Biddy), daughter of the author Ladbroke Black in 1938. They had three children:

• Jeremy Barlow (1939-)
• Camilla Barlow (1942-), married Martin Christopher Mitcheson and later Anthony Whitworth-Jones
• Phyllida Barlow (1944-), married Fabian Peake.

External links

• Obituary, Cambridge Evening News.
• Obituary in British Medical Journal.