LONDON — The U.K. Independence Party, and especially its flamboyant leader Nigel Farage, were a major force behind Britain’s referendum to leave the European Union, a vote stoked by white British anxieties over immigration and multiculturalism.

Farage was popular enough that President-elect Trump tweeted that he should be named British ambassador to the United States.

Ever since its victory in the Brexit referendum in June 2016, UKIP has been circling the drain, with a series of high-level defections and nothing but ruin at the polls. Farage resigned, replaced by four party leaders in 18 months. In the last elections, UKIP failed to win a single seat in the House of Commons.

Now more scandal: The latest leader of UKIP, ex-cop Henry Bolton, a 54-year-old former soldier, is struggling to hold onto his post after a British tabloid published a string of racist text messages penned by his new 25-year-old girlfriend Jo Marney — posts disparaging  American actress Meghan Markle, who is engaged to marry Prince Harry in May.

Markle’s father is white, and her mother is black.

In a series of private posts sent to a friend, Marney worries that Prince Harry’s “black American” fiancee will “taint” the Royal Family with “her seed” and make way for a “black king.”

According to the posts, reported by the Daily Mail, Marney also says she would never have sex with “a Negro” because they are “ugly.”

“Not my thing,” she wrote.

Marney also called Markle a “dumb little commoner” with a “tiny brain” who is “obsessed with race.”

Her friend posted in reply, “racist.”

Marney answered, “LOL so what? Not wanting other races and cultures to invade your own culture doesn’t mean I hate their race. Just means I don’t want their cultures invading mine.”

On Twitter, Marney describes herself as “Presenter. Music Journalist. Model. Actor. Brexiteer.”

Marney was also a UKIP activist who was forced to resign from the party.

She and UKIP’s leader Bolton began dating just before the Christmas holidays. He is 54. She is 25.

British media reported that senior UKIP members had given Bolton an ultimatum: Resign immediately or split with Marney.

In a painfully awkward interview Monday morning on BBC Radio 4’s “Today” program, Bolton announced the couple were no longer an item.

“The romantic element of the relationship is over, I’m afraid, as of last night,” Bolton said.

The UKIP chief said he had began his romance with Marney just a month ago. There were photos of the two, arm in arm, posted on social media celebrating their coupledom on the Christmas season’s Boxing Day holiday.

On Monday, Bolton said, “I have no intention of resigning.”

Bolton called Marney’s comments “indefensible,” but added, “I’ll be entirely honest, however appalling and insulting those comments that they made in those direct personal messages are, I honestly don’t believe that those are her core beliefs.”

Bolton also said he would not completely abandon Marney.

“I’m going to stand by her and the family in terms of trying to put her life back together. This is not a cold parting of the ways,” he said.

For her part, Marney told the Mail on Sunday: “The opinions I expressed were deliberately exaggerated to make a point and have, to an extent, been taken out of context. Yet I fully recognize the offense they have caused.”

On Monday, as a wave of social media shaming crashed around her, Marney tweeted, “Drenched! Need a poncho.”

One supporter replied, “I am with you and I feel you have been hung out to dry!!”

Marney replied, “We all make mistakes. It’s how you deal with those mistakes and conduct yourself in the future that matters.”

Yet in much of the Twitter thread, Marney is branded by many as an unrepentant racist. Others posted photographs of Marney posing as a glamour model beside images of Prince Harry’s fiancee, suggesting she was motivated in part by jealousy. Still other posts were lewd and threatened Marney with sexual assault.

On BBC 2’s “Daily Politics” program, a former leadership candidate for UKIP, Bill Etheridge, said: “We had great hopes for Henry Bolton. He promised us he’d be the sensible pair of hands after a very rough journey over the last couple of years with so many different leaders. But unfortunately he wasn’t, was he? So I don’t think he has much choice.”

During his rounds of the talk shows, Bolton also revealed his wife and two young children live in Vienna.

“We’re not legally separated or anything, but my wife has been in Austria since July with our two children, and that was a move she made by mutual agreement,” he told the BBC radio show.

At one point, he said the decision to live apart was “financial.”