No, Teribus! You contended that Clark had admitted that he had invented the phrase itself.

Clark called his book The Donkeys, based on the well-known - as you have now admitted - phrase 'lions led by donkeys'.

Nigel Rees - in his book A Word in your shell-like (2004) - provides a long history for the phrase, certainly back to the Crimean War.

And Wikipedia even provides a record of its use in the Grosses Hauptquartier. Evelyn, Princess Blücher, published her memoir 'An English Wife in Berlin' in 1921. She recalled hearing German general Erich Ludendorff praise the British for their bravery and remembered hearing first hand the following statement from the German General Headquarters:

"The English Generals are wanting in strategy. We should have no chance if they possessed as much science as their officers and men had of courage and bravery. They are lions led by donkeys."