This remark is also widely attributed to Napoleon Bonaparte, but I can find no verifiable attribution to either Churchill or Napoleon.
On its Pol Roger page (this was Churchill's favourite brand), Wikipedia notes that "Churchill was oft to repeat Napoleon's maxim on champagne: 'In victory, deserve it. In defeat, need it!'"
A blog entitled The Big Apple (by one Barry Popik) has an extensive list of references, including attributions to both Churchill and Napoleon, but none of which really manages to pin it down. It does say in the introduction that Churchill wrote it in 1946, but doesn't give a reference.
The truth would appear to be that Churchill probably did write it, but he didn't make it up. Napoleon may or may not have said it, but even if he did, he may not have been the originator.
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