Brexit is an opportunity for Brits to put up or shut up.

Britain's independence from the Brussels-based European Union, which will kick in after a transitional period that ends on December 31, means Britain's final, trifling excuse for what Brits often deride as the food nanny state will soon evaporate. Starting January 1, 2021, if Britain is still a nanny state, it no longer will have anyone or anything to blame on the continent.

There's a sliver of hope the country will make good. In July, Sky News reported that candidate Boris Johnson, now Britain's Prime Minister, had "declare[d] war on the 'nanny state.'"

During a pre-election speech, Johnson famously "brandished a smoked kipper on stage… as he blasted European Union food rules as a reason to get Brexit done." A kipper smoker on the Isle of Man, Johnson explained, had complained to him that E.U. packaging rules—which he said required the use of "ice pillows"—were killing the kipper smoker's business.

While Johnson's fervor was admirable, the incident revealed a small problem: E.U. regulators pushed back forcefully, claiming that the packaging regulation was British in origin (rather than an E.U. rule) and noting that, anyways, the Isle of Man is not a member of the E.U.

(Whether or not the rule in question is of E.U. or British origin, it is my sincere hope that the expression "brandishing a kipper" becomes the rallying cry for eliminating senseless food regulations, much like the expression "cutting red tape" calls for eliminating senseless regulations generally.)

If Johnson's kipper tale seems appropriately fishy, there's more reason to be skeptical. In 2016, a Financial Times piece on Johnson noted the then-London mayor had both railed against "'nanny state' dietary advice in 2005 then, a decade later, impos[ed] a sugar tax at City Hall's café."

Other times, though, Johnson says things that make a lot of sense.

Shortly before Johnson took office, U.K. Secretary of State for Health and Social Care Matt Hancock released a report adding milkshakes to the list of drinks subject to Britain's sugar tax. Johnson responded that he'd investigate whether such policies work (they don't, but hardly any government ever ponders this fact) and if they disproportionally impact low-income consumers (they do, but hardly any government ever ponders this fact).

"The recent proposal for a tax on milkshakes seems to me to clobber those who can least afford it," Johnson said. "If we want people to lose weight and live healthier lifestyles, we should encourage people to walk, cycle, and generally do more exercise. Rather than just taxing people more, we should look at how effective the so-called 'sin taxes' really are, and if they actually change behavior."

In a January 2019 column, I noted that Great Britain is in the midst of a grand debate over food and the nanny state. I welcome that debate, even if it's nowhere near clear that opponents of overzealous, needless, and pervasive food regulation have the edge. Indeed, British journalist Christopher Snowdon last year called Britain "one of the worst nanny states in Europe."

Will Brexit change that?

The promise of Brexit, I wrote in September, is that "post-Brexit Britain emerges as a beacon of free trade and prosperity." But it could just as easily turn insular and protectionist and ramp up its nannying ways.

It's still far too early to know whether Brexit's promise or peril will prevail.

Keep an eye, though, on the nanny state. Brandishing a kipper to nanny state rules inside Britain's own borders is both (in terms of expectations) a promise of Brexit and also (quite literally) a promise made by Boris Johnson to Britons. Let's see if they deliver.