LONDON — Europe’s biggest city is about to elect a mayor who may be banned from entering the United States if Donald Trump is elected president.

Labour's Sadiq Khan, a practicing Muslim whose parents moved to Britain from Pakistan, is on course to crush his Conservative rival Zac Goldsmith in Thursday's vote, with a double-digit lead in opinion polls.

His rise comes despite a campaign orchestrated by Tory HQ — with the help of PR firm co-owned by Prime Minister David Cameron’s Australian election guru Lynton Crosby — to paint him as a friend of extremists. Khan has also had to contend with a storm of controversy over allegations of anti-Semitism in the Labour Party.

The former London mayor Ken Livingstone sparked outrage after defending a Muslim Labour MP who had called for Israelis to be transported to the United States. Labour left-winger Livingstone also claimed Hitler was a Zionist.

In his bid for a job that would make him Europe's most powerful Muslim politician, 45-year-old Khan was already battling against a rise in Islamophobia since the Paris and Brussels attacks, which revived memories of the 2005 London bombings. He knows the anti-Semitism row could hurt his chances of winning over a city with 170,000 Jewish voters.

"Where else do you get a politician of Islamic faith opening his fast in Jewish synagogues?" — Sadiq Khan

But London is not the same as the U.K. nor Europe. One of the world's most diverse cities, more than 40 percent of its population is from an ethnic minority, compared to 16 percent in the U.K. as a whole.

Khan urges his campaign volunteers to go “street to street, from synagogue to mosque, church to gurdwara.” Outside London they’d be walking a long time to get from the village church to the local gurdwara.

A practising Muslim who prays five times a day and fasts for Ramadan, Khan is every bit the Londoner, born and brought up on a low-income housing estate in south London by a stay-at-home mother and bus-driver father. Also very much the metropolitan liberal, he says he's proud to win votes from “Muslims, Jews, Christians, Buddhists, Hindus, Sikhs” as well as those “who aren’t members of organised religion — gay, lesbian, black, white, rich, poor, old, young.”

"London is a beacon for the rest of the world,” he told POLITICO. “Where else do you get a politician of Islamic faith opening his fast in Jewish synagogues? That’s the London that I know. We don’t tolerate difference, we respect it and celebrate it. That’s the London story — why would you want to divide that and cause problems?”

Londonistan

Khan is alluding to his rival Zac Goldsmith, whose campaign has been accused of adopting “dog-whistle tactics” by focusing heavily on Khan’s associations with extremists.

David Cameron attacked Khan during Prime Minister’s Questions for repeatedly sharing a platform with the preacher Suliman Gani, who has called for an Islamic state and labeled women “subservient.”

It was such people, alongside the tabloid hate figures Abu Qatada and Abu Hamza — both now extradited from the U.K. — who epitomised “Londonistan,” Europe’s center of Islamist fanaticism before that unwanted mantle passed to Paris and Brussels.

Labour believes the Tory campaign has been heavily influenced by Crosby, who is known for using immigration as a dividing issue. The Tories insist Crosby has nothing to do with the contest campaign, but his business partner Mark Fullbrook has been seen campaigning with Goldsmith.

"The Labour Party has a really serious problem with anti-Semitism" — Zac Goldsmith

The Conservative candidate, son of billionaire financier Sir James Goldsmith, told POLITICO it was “completely irresponsible” of Labour to accuse his campaign of racism.

“There is a growing concern around security, not surprisingly because of what has been happening in Europe — Brussels, Paris and so on," he said. This is not about Khan, said Goldsmith, but “how are you going to keep London safe.”

“You can’t stand for mayor of London — the greatest city in the world, the most important city in the world, a job with a big security remit — and not expect your extensive links to people who wish to do this city harm to come under scrutiny," he said.

“People understand — I’m not questioning Sadiq Khan’s world view or his priorities — but I am questioning his judgement. Judgement matters for somebody who wants to be mayor of London," said Goldsmith, broadening his argument to the current allegations of anti-Semitism in the Labour Party under Jeremy Corbyn, who has voiced support for Hamas and Hezbollah.

“The Labour Party has a really serious problem with anti-Semitism and it runs right the way through the party," said Goldsmith, who is father was Jewish and who has reported receiving anti-Semitic abuse on Twitter.

But Chuka Umunna, the Labour MP for Streatham, south London, whose late father was Nigerian, accused the Tories of trying to “segment up the ethnic minority vote” by targeting Hindu, Sikh and Jewish voters.

He said the Tories had made a calculated decision that they could “afford to offend” Muslims because they voted Labour.

“I’ve spoken to current and former senior Conservative ministers who abhor the campaign they are running against Sadiq. There are quite ashamed of the campaign that they are running — it’s really base politics of the worst kind.”

'I love America'

Christopher Curtis from the pollsters YouGov, however, said there was “no evidence” that a large number of people were concerned by Khan’s religion or race — or , indeed, that people knew who the candidates were or would vote on anything other than party lines. "This is a massively Labour city. If it’s Labour versus the Tories then Labour wins,” he said.

"This is someone who is going to be the most senior Muslim politician in Europe" — Chuka Umunna, MP

Khan has a 16-point lead for the first round, rising to 20 points in the second, meaning Goldsmith "has a massive mountain to climb to win this election," said Curtis. Compared to the 2012 vote when the Tories' Boris Johnson beat Labour left-winger Ken Livingstone, this time round "the Conservative candidate is not as good and the Labour candidate is better," said the pollster.

Umunna said it was “remarkable” to see how little people cared about race or religion in a contest that was "on the cusp of electing the first Muslim mayor of a major European city."

“This is someone who is going to be the most senior Muslim politician in Europe, let alone Britain. It is a tribute to London — Londoners are more interested in what this extremely talented man has to say on the issues,” said the MP.

The issues that have dominated the campaign are housing and transport, he said, rather than "that Sadiq is a Muslim." Umunna said that would not have been the case 15 or 20 years ago when he was growing up, and was a sign that Londoners are "more diverse and more comfortable in our skin."

Khan's religion could become an issue, however, if Trump become president of the United States and introduces his “complete shutdown” on Muslims entering the United States.

"I’m hoping he doesn’t win. I’ve got family in America who are Muslim — I love America,” Khan told POLITICO.

“I visit there frequently — it’s a great country. But as the mayor of London I could be stopped from going there to meet Bill de Blasio, Rahm Emanuel or other Americans because of my faith. That’s not the America I know and love.”

In January, the front-runner for the Republican nomination stirred further controversy in the U.K. by claiming there were “places in London and other places that are so radicalized that the police are afraid for their own lives.”

Despite Trump’s call for Muslims to be banned from the U.S., Khan does not want the ban reciprocated.

“It would be good for Donald Trump to come to London — but also parts of America — and meet people who are comfortable being American and Muslim and British and Muslim," he said.