Knaggs» career reached a
peak in the mid -»40s, when he worked in supporting roles in
ambitious major studio films such as None but the Lonely Heart (a fascinating but failed attempt at a serious drama by Cary Grant) and unusual independently made features like Douglas Sirk's
early Hollywood effort Thieves» Holiday, while also making the rounds of such popular medium - budget Universal Pictures productions as House of Dracula, The Invisible Man's Revenge, and Terror By Night.