Commanded the 11th Battalion Worcestershire Regiment from July 1942 to December 1942.
As a Lieutenant he was appointed Adjutant of the K.S.L.I. on the 16th July 1932 a position he held until 16th July 1935. Having been promoted to the rank of Captain on the 16th may 1935.
There followed a period at Staff College and on the 1st July 1939 he was appointed G.S.O. Grade 3 on General Staff a position which he held for the first few years of the Second World War.
Promoted to Major on the 29th January 1942. He was appointed to Command the 11th Battalion Worcestershire Regiment in July 1942 as Acting Lieut.-Colonel. On the 1st January 1943 the 11th Battalion was disbanded to form the basis of the reconstituted 1st Battalion Worcestershire Regiment and Lieut.-Colonel Cox continued to command the 1st Battalion until September 1943 when he left to take up a staff appointment.
As Acting Brigadier he was awarded the D.S.O. on the 1st March 1945. He also received a Mention in Despatches (London Gazette 22nd March 1945). As Temporary Brigadier he received a seconded Mention in Despatches on the 4th April 1946.
As a Major (war substantive Lieut.-Colonel) he was promoted to full rank of Lieut.-Colonel on the 18th September 1946 and on the 20th April 1949 promoted to Colonel.
In 1948 when he was with B.G.S., Western Command, he was awarded the Military Cross of the Czechoslovakian Order of the White Lion, 3rd Class, 1939. (Gazette date 14th May 1948).
On the 13th June 1953 he was promoted to Brigadier and held a staff position as Deputy Director of Infantry.
Brigadier W. R. Cox, DSO
(known as "Bill")
Appointed General Officer Commanding Mid West District and 53rd (Welsh) Infantry Division (T.A.) on the 25th March 1955.
Promoted to Major-General on the 28th March 1955.
Major-General Cox was awarded the Companion of the Order of Bath on the 2nd January 1956.
The following year, on the 5th November 1957, he was appointed Colonel of the King's Shropshire Light Infantry. He held this appointment until 5th November 1963.
Relinquished his appointment as General Officer Commanding, Mid West District and 53rd Infantry Division (T.A.) on the 6th January 1958.
On the 10th February 1958 he was appointed Director, Territorial Army, Cadets and Home Guard. He held this post until 20th August 1960 and the following day he retired from the Army but continued to remain on the Officers Reserve list until 13th June 1965.
Major-General William Reginald Cox, died at Salisbury on the day before his birthday on the 12th June 1988, aged 82. His funeral was held on the 17th June 1988 at Amesbury Church.