According the story, the boys were told that Churchill, as Prime Minister
of Great Britain was a very wise man and they should listen very carefully
to what he would tell them. The were ushered into the school hall and
sat ready to hear to words of the great man.
At the appropriate time in the assembly, Churchill was introduced
to the boys. He stood up solemnly, looked at the boys and said “Never
give in, never give in, never, never, never, never give in.”
(Updated Churchill link 4/4/2010)