Military The Navy, Army and Air Force Institutes, which runs the canteen in all H.M. ships and all Service establishments. The three Services each provide four members of the Council and one member of the Board of Management. 
Non-profit-making association providing canteens for HM British Forces in the UK and abroad. ...
[Naval Acronyms and Slang] Navy Army and Air Force Institutes[Naval Acronyms and Slang] Not At All… . You can guess the rest. Extremely derogatory but still funny[Naval Acronyms and Slang] Various derogatory words to describe above. There are too many… a bit offensive, but all in good fun
Navy, Army and Air Force Institute
Navy, Army, and Air Force Institutes: an organization that provides social facilities, stores, etc., to British military personnel. · a canteen run by this organization.