Politely telling someone that he has lied

Short clip of a wonderful exchange between Sir Humphrey and the Prime Minister. In case you want to memorise it for a suitable occasion:

Yes. Unfortunately, although the answer was indeed clear, simple and straightforward, there is some difficulty in justifiably assigning to it the fourth of the epithets you applied to the statement, inasmuch as the precise correlation between the information you communicated, and the facts insofar they can be determined and demonstrated, is such as to cause epistemological problems of sufficient magnitude as to lay upon the logical and semantic resources of the English language a heavier burden than they can reasonably be expected to bear.

I found this clip after playing the one about Modernism in the Church of England which was posted by Mundabor.