colonel-in-chief 
noun (plural colonels-in-chief)
A title given to the honorary head of a regiment in the British army.She was colonel, honorary colonel or colonel-in-chief of more than a dozen regiments and units....
- The Duke of Gloucester is the colonel-in-chief of the Royal Army Medical Corps and the duchess is the colonel-in-chief of the Royal Army Dental Corps.
- The colonel-in-chief was visiting the 1st Battalion, The Cheshire Regiment as soldiers prepared to go on a six-month peacekeeping mission to Basra in April.