Longest palindrome I know

The longest palindrome that I know was from a professor with whom I took a history class. It is the following: Dog sex at noon taxes God. (20 letters)

I learned one today that is even longer: Golf? No sir, prefer prison flog! (25 letters)

Granted of course, you could categorize it as the following: The first one is the longest one I know with only one period at the end of the sentence (i.e. a phrase, or a simple sentence), while the second one takes into consideration multiple punctuations (i.e. a more elegant sentence).

Either way, it's cool.