Talking with a friend over lunch today about the value of brevity in communication and he described going to the  Union quite soon after his arrival in Cambridge, to see a debate featuring, among others, Lord Lever and Norman Lamont. Lever proved a very nervous public speaker, gabbling his words while his notes shook visibly in his hands. After a few minutes, Lamont quietly handed him a piece of paper. From his vantage point in the balcony directly overhead, my friend saw that it bore three words, in clear block capitals:

SLOW DOWN

LOUDER

His Lordship took note; the remainder of his speech was a vast improvement.