Derrick Norrington Cronin was born on the 7th September 1911 at Kings Norton. His mothers maiden name was Crapnell.
He was educated at King Edward's School, Birmingham and joined the school's O.T.C.
On the 21st December 1935 he was granted a T.A. commissioned into the 7th Battalion Worcestershire Regiment as a 2nd Lieutenant, and served with "C" and "D" Companies at Langley, Oldbury and Halesowen. He was promoted to Lieutenant on the 21st December 1938.
He was transferred to the 9th Battalion on its formation in August 1939, and served with this Battalion as a Company Commander and Second-in-Command during the war, in Northern Ireland and on the South-East Coast.
He was promoted to rank of Captain on the 11th April 1945.
He was awarded the M.B.E. (London Gazette 1st January 1946) for his war service.
He was promoted to rank of Major on the 1st May 1947. On the re-formation of the 7th Battalion in 1947, he was Second-in-Command. On the 1st May 1951 he was promoted to Lieut.-Colonel and took command of the 7th Battalion in June 1951.
During his command of the 7th Battalion he was involved in the notorious "Z" call-up. Also the 7th Battalion gained the Freedom of the Borough of Kidderminster, and the Presentation of New Colours by H.R.H. The Princess Royal.