As a contribution to the war effort Heilbronn organised the Trinity College A.R.P. Fire Service. However, he was interned on the Isle of Man in 1940 as an enemy alien, something which he greatly resented since nobody could have been more opposed to the Nazis than he was.
Bilang isang kontribusyon sa digma pagsisikap Heilbronn organised ang Trinity College ARP Fire Service. Gayunman, siya ay interned sa Isle of Man sa 1940 bilang isang dayuhan na kaaway, isang bagay na kung saan siya malaki resented dahil walang sinuman ay maaaring magkaroon ng higit pa na-kontra sa Nazis kaysa sa siya.