Major Collin had a long and eventful career in the British Army, spanning the Boer War to the First World War. He joined in January 1900 into the 4th Battalion as a 2nd Lieutenant. By December 1900 he had been promoted to Lieutenant. Edgar went on to fight in the Boer War of 1899-1902, having served in multiple campaigns during the conflict. Edgar was even taken prisoner for a short while whilst fighting with the 4th Battalion. 

In April 1902 Edgar transferred to a regular commission with The Sherwood Foresters as a 2nd Lieutenant. He would be promoted to Lieutenant on the 25th of April 1906 and Captain on the 2nd of September 1912. In 1913 he had taken a post as Captain and Adjutant of 8th Battalion and was a Major by 1916.  

In August to September 1916 Edgar moved to The Worcestershire Regiment.  He was appointed second in command of the 2nd Battalion and then returned to the 1st Battalion Sherwood Foresters taking temporary command.  Major Collin had been appointed Camp Commandant Curlu, by February 1917. He retired in 1922. 

 He sadly passed away in 1953.