Winston Churchill's push to obtain penicillin in time to treat casualties expected from D-Day has come to light in documents seen by BBC News.
Official papers unearthed by the National Archives reveal the prime minister's frustration and concern over slow progress securing supplies of what was then seen to be a brand new "wonder drug".
The BBC was shown the papers ahead of the anniversary of the Normandy landings on 6 June 1944.
Even months after D-Day, the wartime prime minister called efforts "very disappointing" and bemoaned the fact the US was "so far ahead" despite the drug being a "British discovery".
Penicillin was discovered in London by Professor Alexander Fleming in 1928. Despite attempts to produce a usable medicine from the bacteria-killing mould, this had not been achieved by the start of World War Two.
