Though the quote has been attributed by some to Prime Minister HH Asquith, it is more usually felt to have been uttered by his wife Margot, who dispised Kitchener. She also came up with one of my avourites. When the Hollywood actress Jean Harlow mispronounced her name, Margot replied: "The 't' is silent, as in 'Harlow'." Margot was also, fact-fans, the great-grndmother of Helena Bonham Carter.
The quote is variously given as "If Kitchener was not a great man, he was, at least, a great poster" or "He was not a great man, but at least he was a great poster."