LONDON — Just two days before the British Parliament is scheduled for a historic vote on Brexit, several thousand marchers — edgy, suspicious, aloud with conspiracy theories — massed near Prime Minister Theresa May’s official residence at 10 Downing Street on Sunday to condemn her as a traitor to their cause.

The march was called by the U.K. Independence Party (UKIP), a once-ascendant movement now in decline, dominated by “Euroskeptics” and right-wing populists. They were at the forefront of the winning Brexit campaign two years ago, when they were led by radio show personality and Fox News contributor Nigel Farage, who was one of the first British politicians to meet with President Trump after his election. 

Now the Ukippers and their allies at the rally say they are being double-crossed by “the establishment,” aided by a “seditious BBC,” and a deep state of pro-Europe civil servants and global capitalists led by May.

Pro-Brexit protesters marched in London Dec. 9. They held signs decrying a deal Prime Minister Theresa May struck with Europe, which faces a vote in Parliament. (AP)

In the crowd, one man held aloft a gallows with a hangman’s noose. Others shouted that May should be “taken to the Tower,” the medieval palace-prison where Henry VIII had his wives killed. 

At the rally, the current leader of UKIP, Gerard Batten, called May’s Brexit plans “a betrayal” that had created “the biggest crisis since the English civil war” in the 1640s — which saw Charles I beheaded.

The demonstrators said May’s deal to leave the European Union — which she has called an “honorable compromise” — was actually a ruse designed to produce no Brexit at all.

“It’s going to be voted down. That was her plan all along, wasn’t it?” said Paul Oakley, the general secretary of UKIP, referring to Tuesday’s vote in Parliament, where many members of May’s own Conservative Party have said they will vote against her Brexit deal.

Oakley reminded the crowd that in the June 2016 referendum, May voted to remain in the European Union. “This woman is not stupid,” he said. “You simply do not become prime minister unless you possess deep cunning. She always intended to betray Brexit.” 

The UKIP lineup of speakers included Tommy Robinson, a felon and founder of the English Defense League, a far-right movement, who said he was prosecuted for campaigning against “the Islamization of this country.” He was jailed after photographing defendants in a sex ring run by 20 men, mostly of Pakistani descent, against a judge’s orders not to reveal their identities while their trial was underway.

Robinson, who is now a paid adviser to UKIP, told the audience: “To be honest, up until this point, I didn’t believe in democracy. I never thought they would let us leave. I’m still not sure they’ll let us leave.” 

As the UKIP “Brexit Betrayal” march was underway, larger numbers of counterprotesters came out in central London, some to oppose the Robinson crowd and others to support a second referendum, dubbed a People’s Vote, to allow citizens another chance to decide whether to go forward with May’s Brexit.

In the placards and speeches at the UKIP rally, May was condemned as an enemy of the people. The atmosphere showed how Brexit — described by some as the most momentous decision in a generation — is rubbing the usually staid Brits raw.

Many have aligned themselves into two warring camps — “remainers” and “leavers.” 

On social media and the Sunday morning political talk shows, the sides continued to do battle over the best way forward. It seems there is little hope for finding common cause. The polls are as divided as ever, and the political class is either plotting against May or running for the exits.

Some of May’s fellow Tories pushed Parliament to support her unpopular plan as the best deal possible; others said the country should risk the economic chaos of a “no deal” Brexit and just crash out of the European Union.

Others urged May to return to the negotiating table to seek better terms, but the Europeans have signaled there is no other deal to offer.

The London Sunday Times reported that May’s ministers and aides “expect May to announce tomorrow that she will launch a final throw of the diplomatic dice with a dash to Brussels, a move that could result in Tuesday’s vote being postponed.”

Others called that wishful thinking.

The former foreign secretary and arch Brexiteer Boris Johnson said Sunday that a “great” deal with the European Union was still possible — though he was vague about how it would be accomplished.

The Telegraph reported that “at least nine current or former cabinet ministers are understood to be contemplating running for leader” if May is either forced out or resigns if her withdrawal agreement is defeated in Parliament.

Johnson is considered a top contender, and political handicappers speculated that the race may be on — because the mop-headed Johnson sported a new haircut.

For her part, May said she copes with the stress of Brexit by eating spoonfuls of peanut butter out of the jar.

The prime minister also warned that if her deal was defeated and she were chucked out, the Conservative Party would be facing Labour Party leader Jeremy Corbyn.

“Getting his hands on power is a risk we cannot afford to take,’ she told the Daily Mail.