I eat steak whenever I'm in the United States. Your steaks are bigger, juicier, and more tender than those I can buy in Europe. Why? Partly because American cattle are given hormones that are banned in the EU.

Now, you might prefer the idea of unadulterated beef, raised only on rich green grass. Plenty of people in Europe say they do, and good luck to them. No one is going to force them to eat anything they don't want. But why should they impose their taste on the rest of us?

Over the past two weeks, a bizarre alliance has coalesced in Britain against the import of American food, in particular beef and chicken (which, being washed in chlorine, is also outlawed by the EU). A post-EU Britain will be free to sign a trade deal with the U.S., removing the more superstitious restrictions, thus lowering costs for British consumers. Who could be against that? Quite a few people, it turns out — anti-Americans, Leftist agitators, militant vegetarians and, not least, Euro-fanatics who want Brexit to fail, and so oppose any post-EU trade deals. Plus, of course, some U.K. farmers who, like all producers in all countries, want to keep out competition.

If a U.S.-U.K. trade deal is consumer-led, removes irrational barriers, and asserts the basic principle that what may be sold in one country may legally be sold in the other, the potential gains are vast.

Here, though, is the key point: The biggest gains are to the country that sweeps away its own barriers. Sure, there will be some gains for Nebraskan ranchers if Britain allows U.S. beef into its markets. But the real advantage goes to the Brits. As prices fall in the U.K., time and resources which would otherwise have gone on purchasing food are freed up to make and sell other stuff.

That idea is counterintuitive. The desire to be self-reliant is wired into our brains, and economic protectionism is an extension of our Paleolithic instincts. For many decades, countries around the world condemned themselves to perennial hunger because they thought they had to be self-sufficient in food. It was only in the 1960s that the world came to understand that buying from multiple sources at international prices was, paradoxically, a far more certain way of ensuring its supply than trying to produce it all yourself.

Even today, many policymakers and, indeed, most voters think that exports matter more than imports. Trade negotiators often see it as their task to open up as much of the other party's market as possible while protecting key domestic sectors.

Consider, for example, an op-ed in the Wall Street Journal last week by Wilbur Ross entitled "Free Trade is a Two-Way Street." The secretary of commerce complained that "China and Europe bankroll their exports through grants, low-cost loans, energy subsidies, special value-added tax refunds, and below-market real-estate sales."

Yes, they indeed do that. And consequently, American consumers get a free gift from European and Chinese taxpayers.

Ross complains about "our $752.5 billion trade deficit in goods," and most readers will sympathize. But think about it. Why is it a bad thing to be getting more goods than you send out? It's not so much a trade deficit as a goods surplus. If my local supermarket sells me stuff more cheaply, and I take more of it home, how am I harmed? If it is selling to me at below cost price — in other words, if it is subsidizing me — then lucky me.

This is, as I say, a difficult idea, running up as it does against ancient intuitions. But listen to Milton Friedman: "We're getting more goods coming in (imports) and sending out fewer in return (as exports). Each of us in our private households would know that is beneficial. You don't regard it as a favorable trade imbalance when your household has to send out more goods to get fewer coming in (i.e., a trade surplus). It's a favorable trade imbalance when you can get more by sending out less (i.e., a trade deficit)."

Yes, Oklahoma cattlemen will gain incidentally from a comprehensive U.S.-U.K. deal. But, by far, the larger benefit will be to American consumers if, for example, the principle is established that drugs approved by one of the two countries may be automatically sold in the other. That would break the pharmaceutical cartel in the U.S. and bring prices tumbling down. The same applies to the mutual recognition of professional qualifications. The more we extend choice and competition, the better for everyone.

Secretary Ross is right that Brussels and Beijing have never really grasped free trade. London and Washington now have a chance to do better.

Dan Hannan is a British Conservative MEP.