President-elect Trump is in like Flynn with America’s most enduring “special relationship.” For though his electoral victory is the cause of protests at home and unease at European capitals, “Mr. Brexit” basks in favorable reviews from the British government. Small wonder. Both nascent administrations swept to office on a wave of anti-establishment populism.

Leading the welcoming party are Brexiteers who spearheaded efforts to take the United Kingdom out of the European Union and regain the sovereign powers it had ceded to the continent. UKIP’s former leader, Nigel Farage, calls Mr. Trump “instinctively Anglophile;” Britain’s foreign secretary Boris Johnson is urging EU colleagues to cease their “collective whinge-o-rama” and accept the incoming American administration. Mr. Johnson, himself New-York born, betrayed affinities for across the pond when he christened the June 23 vote for Brexit Britain’s “Independence Day.”

Prime Minister May, in an address earlier this week at the Lord Mayor’s Banquet, echoed an openness to Trump. Mrs. May, who became premier when her pro-EU predecessor David Cameron resigned following the vote for British independence, began by noting their joint brash rise to high office: she, to “forge a bold, new confident future for ourselves in the world;” Mr. Trump, “who defied the polls and the pundits all the way up to election day itself.”

So 2016 is the year of change politics and “when people demand change, it is the job of politicians to respond.” Mrs. May has reason to sympathize with Mr. Trump, as both will be contending with obstructionists. In London, a High Court has ruled that the government must bring legislation to Parliament before it can trigger Article 50 to begin negotiating an EU exit; whereas Mr. Trump continues to face political and press protests against carrying out the campaign promises the voters backed — the repeal of ObamaCare, a wall along the southern border, an end to certain multilateral trade deals.

Both leaders face opposition not only from political adversaries but from members within their own rank-and-file (Senator Rand Paul just announced opposition to John Bolton or Rudolph Giuliani as secretary of state). Both Mrs. May and Mr. Trump can take consolation in the support of the middle class — “the forgotten man and woman” — that has seen its jobs, values, and patriotism ridiculed or ignored by the “global elite.” For both, the cause for popular revolt is obvious: “the forces of liberalism and globalism” reigning in Britain, America and Western Europe “have left too many people behind.”

Like Mr. Trump, Mrs. May’s antidote lies in economic growth, or, as Mrs. May puts it, by “getting Britain firing on all cylinders again by creating the conditions where winners can emerge and grow, across all sectors, in all parts of the country and for the benefit of all.” Unlike Mr. Trump, though, Mrs. May sees the path to restoring Britain’s place in the world not through tariffs and protectionism but through free trade, stating “there is no contradiction between embracing globalisation and saying it has to be managed to work for everyone.”

This may yet evolve as Mr. Trump’s stance on trade, too, factoring in his determination to end foreign currency manipulation and the Federal Reserve’s own zero-interest-rate-policy that has contributed to what Mr. Trump characterizes as a “false economy.” Yet Mrs. May’s advocacy of “a new industrial policy” is not without peril, as it conjures up, in her own words, governments “propping up failing industries or picking winners” and almost invariably standing with the white elephants. (Can anyone say “Solyndra?”).

Mrs. May favors some state intervention, as in providing university funding to take advantage of emerging opportunities. Team Trump has echoed this “hands-on” approach for America, whether in the form of vocational training or rebuilding failing transportation and energy-delivery infrastructure. But the true route to economic growth lies not in past manufacturing accomplishment but in future entrepreneurial success on the home front.

This leads Mrs. May to speak of the importance of being “the strongest global advocate for free markets and free trade” because “they are the best way to lift people out of poverty.” Mr. Trump, after reforming multilateral trade agreements, may match Mrs. May. Unleashing a 21st-century equivalent of the Industrial Revolution grounded in sound money, sane regulatory oversight, and innovative enterprise is the ticket to greatness for Britain and America.

Post-Brexit Britain is eager to exploit this new chapter in concert with Donald Trump’s America. “He is after all a deal maker,” Boris Johnson enthuses. “He wants to do a free trade deal with the UK.”

Mr. MacLean edits the Organic Tory.