LONDON — President-elect Trump, about to return to power in Washington after a historic comeback, may find a political soulmate in the form of a British conservative political leader with a chance at an epic upset of his own eventually taking over as prime minister.

That’s the implication of the claim by the minority Reform UK Party, led by Nigel Farage, that it’s outstripped the venerable Conservative Party in numbers of members. “We consign the failed Conservative Party to the history books,” Reform UK boasts on its website. “We overtook the Conservatives at 131,680.” 

Reform UK counts on more members than the Conservatives in the wake of opinion polls showing the once marginal party catching up in overall popular support, though it’s disputed by the Conservatives.

“Is Reform really pulling ahead of Labour,” asked the website, Conversation UK. It reports on a poll by a market research agency, Find Out Now. The poll finds that 26 percent still supported the Conservatives. That’s just ahead of 24 percent for Reform UK and only 23 percent for Labour. 

For now, however, Labour remains in charge of the government under Prime Minister Starmer, having taken over in elections in July on a wave of discontent over a succession of Conservative governments. Like his Conservative predecessors, however, Mr. Starmer is already in trouble amid rising prices in a looming recession.

By law he has nearly five more years before the next elections, but he may call elections well before then in hopes of reaffirming support for his government and policies. With only a handful of Reform UK members in parliament, Mr. Farage’s best chance lies in forming a coalition with the Conservatives, known as Tories, in a challenge to Labour leadership.

In an echo of the slogan, “Make America Great Again,” Mr. Farage is identifying, politically and philosophically, with Trump. American friendship and assistance are vital, he believes, in strengthening the special relationship between London and Washington.

“Will Elon Musk give Nigel Farage $100m to make him PM?” asked the Times of London after Mr. Farage met Mr. Musk at Mar-a-Lago. “The Tesla boss, who used his immense fortune to help Donald Trump’s campaign, is turning his attention to Britain,” the paper reported.

The prospect of Mr. Farage getting all that funding as a serious contender for British leadership is inspiring bitter opposition on all sides. “The government is facing mounting calls….for an urgent clampdown that would limit the amount a foreign national can donate via their UK-based companies,” said the Observer, a liberal Sunday newspaper. 

Conservatives also are unhappy about the prospect of Mr. Farage drawing votes away from them, splitting the party at a time when it needs to unite against Labour rule. The only beneficiary, they say, would be Labour.

In that spirit, the Conservative leader, Kemi Badenoch, engaged in a sparring match on X castigating Reform UK’s claim to have more members. “Manipulating your own supporters at Xmas eh, Nigel,” she wrote. “It’s not real. It’s a fake.” 

Getting tougher as she pounded the keys, she went on, “I am sick of the endless lies, smoke and mirrors, stuff and nonsense politics.” Reform UK will “say anything for cheap media hits because they have no plan underneath,” she wrote. “Just rage against the machine.” 

Mr. Farage sees his influence with Trump as crucial at a time when Britain worries about the president-elect imposing tariffs on nations worldwide. The Times of London reports that Mr. Farage is boasting of his “personal relationship” with Trump and his advisers. “The US is our most important relationship in the world,” he was quoted as saying.

He would, he said, “build bridges” with Trump after the newly named British ambassador to Washington, Peter Mandelson, was quoted as calling Mr. Trump “little short of a white nationalist and a racist” — to which a top Trump aide, Chris LaCivita, retorted that Mr. Mandelson was “an absolute moron.”