english spy in germany during ww1-fiction

fiction of english spy in germany in ww1 steals formula for miracle drug (unnamed but obviously penicillin) may have winter in title since set during turnip winter i think due to implied 'soylent green' sausages read in the 1980's or 90's i believe-spy is killed before returning to england with formula

may have letters or numbers in title in place of or with word winter