'Monkey' Blacker commanded the 5th Royal Inniskilling Dragoon Guards from 1955 to 1957. He was then Military Assistant to the Chief of the Imperial General Staff, Field Marshal Sir Gerald Templer from 1958 to 1960. He was appointed Commander of 39th Infantry Brigade in Northern Ireland in 1962 and was then General Officer Commanding 3rd Division from 1964 to 1966.
He was appointed General Officer Commanding-in-Chief, Northern Command in 1969 and then went on to become Vice Chief of the Imperial General Staff in 1970 before becoming Adjutant General in 1973: he held this post until he retired in 1976. In 1974 his home was badly damaged by an IRA bomb.
He was ADC General to the Queen from 1974 to 1976. He was also Colonel Commandant of the 5th Royal Inniskilling Dragoon Guards from 1972 to 1981.
He was awarded the CB in 1967, the KCB in 1969 and the GCB in 1975. He was also awarded the OBE in 1960.
An Amateur Steeplechaser and International Showjumper, he rode in the 1948 Grand National. He rode Pointsman to win the Grand Military Gold Cup at Cheltenham in 1954. He represented Great Britain in Showjumping from 1959 to 1961. He was President both of the British Showjumping Association from 1976 to 1980 and of the British Equestrian Federation from 1980 to 1984. He was a member of the Horse Race Betting Levy Board from 1980 to 1983.
Author of "Soldier in the Saddle" and "Monkey Business", both of which chronicle his time in 23H.