[3] Jenkins was born in Bristol, England and educated at Bloxham School and Oxford University.
Jenkins's introduction to numismatics came during his time at Oxford, while he was studying Classics at Corpus Christi in the late 1930s.
He attended the Heberden Coin Room in the Ashmolean Museum and was introduced to the subject under the guidance of Edward Robinson and Humphrey Sutherland.
His studies were interrupted by the Second World War, during which he served as an officer in the Royal Artillery, from 1944 to 1946 flying as a reconnaissance pilot in South East Asia.
After shorter articles on this topic, he undertook a huge research project on the precious metal coinages of Carthage (working with R.B.