Regarding free trade:

“Proposition is so very manifest, that it seems ridiculous to take any pains to prove it; nor could it ever have been called into question, had not the interested sophistry of merchants and manufacturers confounded the common sense of mankind. Their interest is, in this respect, directly opposite that of the great body of the people.” **

**The Wealth of Nations, 1776, Cannan edition, vol 1, page 458

And so it remains, save only that trade unions should be added to Smith’s list of those who are using ‘interested sophistry’ impede the operation of free trade.