I have not found any evidence that this is a Winston Churchill quotation.
It appears that this particular quotation is often mistakenly
attributed to Winston Churchill.
A man named Peter Rutland wrote a letter to the Washington Post
clearing up the origin of the 'Churchill quote':
?Charles Krauthammer [op-ed, May 25] quotes Winston Churchill as
saying, "If you're not a liberal when you're 20, you have no heart. If
you're not a conservative when you're 40, you have no head."
This quotation is frequently but mistakenly attributed to Churchill.
It is anyway unlikely that Churchill would subscribe to this
philosophy: He was a swashbuckling soldier at 20, and a Conservative
member of Parliament at 25. A couple of years later he switched to the
Liberal Party (which was not liberal in the modern sense), and later
went back to the Conservatives.
The phrase originated with Francois Guisot (1787-1874): "Not to be a
republican at twenty is proof of want of heart; to be one at thirty is
proof of want of head." It was revived by French Premier Georges
Clemenceau (1841-1929): "Not to be a socialist at twenty is proof of
want of heart; to be one at thirty is proof of want of head."
?Any man who is under 30, and is not a liberal, has no heart; and any
man who is over 30, and is not a conservative, has no brains."
?While the sentiment is certainly astute and wise, the saying did not
originate with Churchill. In fact, that wording is a variation of,
"The man who is not a socialist at twenty has no heart, but if he is
still a socialist at forty he has no head?, which belongs to the
former French Prime Minister Aristide Briand, who was himself a
Briand, however, appears to have cribbed the saying from another
French statesman, Francois Guizot (1787?1874), who originally said,
?Not to be a republican at twenty is proof of want of heart; to be one
at thirty is proof of want of head.?
"If a man is not a socialist in his youth, he has no heart. If he is
not a conservative by the time he is 30 he has no head" -- Georges
Clemenceau, Former French Prime Minister and one-time radical. (There
are many versions of this saying and many attributions of it but the
original utterance seems to have been by mid-nineteenth century French
historian and politician Francois Guizot, who said: "Not to be a
republican at 20 is proof of want of heart; to be one at 30 is proof
of want of head". He was referring to the controversy over whether
France should be a republic or a monarchy. ?
Variations on this quotation were later attributed to Disraeli, Shaw,
Churchill, and Bertrand Russell.
?This is an updated variation of an apparently ever-relevant opinion,
first quoted by Guisot, a French monarchist statesman under Louis
Not to be a republican at twenty is proof of want of heart;
to be one at thirty is proof of want of head.
-Francois Guisot (1787-1874)
which was later changed by Georges Clemenceau (1841-1929) into:
Not to be a socialist at twenty is proof of want of heart;
to be one at thirty is proof of want of head.?
If my findings are helpful just let me know, and I will gladly post
this information in the answer box.