FILE - President Donald Trump boards Marine One helicopter on the South Lawn of the White House, in Washington, Nov. 26, 2019.
U.S. President Donald Trump will arrive in London, Dec. 2, 2019, to attend a NATO summit hosted by British Prime Minister Boris Johnson.

LONDON - Britain's politicians are bracing for a two-day visit to London by U.S. President Donald Trump and wondering how the trip may affect the most volatile and toxic British election in decades, one likely to shape the country for generations.

Trump arrives in London Monday for a two-day trip to attend what's shaping up to be a fiery NATO summit, hosted by British Prime Minister Boris Johnson.

With 10 days to go before Britons vote in their third general election in less than four years, the ruling Conservatives are enjoying healthy opinion poll leads, which suggests they have a chance to pull off a 68-seat majority in the House of Commons. However, Johnson's aides are fearful of risking anything that could upset their momentum and reverse the trend.

They worry the norm-shattering Trump may fire off controversial remarks concerning the election, Brexit and a future transatlantic free-trade deal with Britain, one the country would need desperately to compensate for a break with Europe. Johnson's aides are playing for safety first — a caution that's seen Johnson reduce his TV interviews and debate appearances in the final days of the election campaign.

In an era of political upsets and scrambled politics the Conservatives don't want to tempt fate, and last week Johnson's key political adviser, Dominic Cummings, warned the party faithful that the general election is much closer than polls suggest, issuing what he dubbed a "bat signal" to anti-EU voters that Brexit is at risk and they need to turn out and vote Conservative.

"Trust me, as someone who has worked on lots of campaigns, things are much tighter than they seem and there is a very real possibility of a hung Parliament," he said.

Britain's Prime Minister Boris Johnson appears on BBC TV's The Andrew Marr Show in London, Britain, Dec, 1, 2019. (Jeff Overs/BBC/Handout via Reuters)

According to Tony Newton-Dunn, the political editor of the Sun newspaper, a British tabloid with good connections to both Downing Street and Trump advisers, the prime minister's aides have been lobbying for Johnson to avoid any bilateral sit-down with Trump. The aim is to "swerve all controversial one-on-one moments by hosting all 29 NATO state leaders for a reception alongside the queen at Buckingham Palace on Tuesday night."

The White House has confirmed there's no plan for Trump to meet with Johnson, although he will have meetings with German Chancellor Angela Merkel and French President Emmanuel Macron on the sidelines, which could turn fiery following the French leader's recent call for Europe to rethink transatlantic relations and its defense structure. Trump will also have meetings with Danish Prime Minister Mette Frederiksen and Italian Premier Giuseppe Conte.

Johnson is scheduled to conclude the summit with a press conference with NATO Secretary-General Jens Stoltenberg. "Loose tongues can sink ships," a Conservative insider told VOA. "We don't want to give a gift to Jeremy Corbyn," he added, referring to the leader of Britain's main opposition Labour Party, which is trailing the Conservatives in the polls by about 11%.

A U.S. official told reporters in Washington that Trump "likes Prime Minister Boris Johnson personally, but he's absolutely cognizant of not wading into other countries' elections." On the eve of the British election, though, Trump wasn't circumspect, saying Corbyn "would be so bad" for Britain and describing his"friend" Boris Johnson as "the exact right guy for the times."

When asked last week whether he would welcome a Trump endorsement, Johnson responded, "What we don't do traditionally, as loving allies and friends, is get involved in each other's election campaigns."

NHS on future trade deal

Britain's opposition Labour party leader Jeremy Corbyn gestures during a general election campaign event in York, Britain, Dec. 1, 2019.

Corbyn has made post-Brexit transatlantic relations a key issue in his campaign, warning voters that the U.S. will demand Britain's National Health Service be "on the table" in talks on a future trade deal. Johnson and Trump have denied the claim.

In June, the U.S. ambassador to Britain, Woody Johnson, told the BBC that the NHS would be on the table in future trade talks between a post-Brexit Britain and Washington. A few days later during a London press conference, Trump confirmed he expected that would be the case saying in response to a question "everything is on the table." He later walked back his remark.

Last week Corbyn released documents showing that in talks between British and American trade representatives the pricing of U.S.-supplied drugs surfaced, with American officials wanting to lengthen the duration of drug patents currently observed in Britain. They also objected to the overall prices Britain's NHS pays for U.S. pharmaceuticals.

"Longer patents can only mean one thing: more expensive drugs. Lives will be put at risk as a result of this," Corbyn said. He highlighted recent Trump complaints about the "unreasonably low prices" countries pay for American drugs.

Conservatives dubbed Corbyn's claim a "stunt."

"The NHS will not be on the table in any future trade deal and the price that the NHS pays for drugs will not be on the table," said the Conservatives' Liz Truss, the current international trade secretary.

Analysts say American health care firms want to expand in Britain but that there's no evidence to date that a trade deal would depend on some kind of dismantling of Britain's state-owned health-care system.

Political vision of Nigel Farage

At the other end of the political spectrum, Brexit Party leader Nigel Farage, a Trump ally and friend, is also hoping Trump's visit will benefit him and give a lift to his flagging electoral prospects. His aides say he hopes Trump might be drawn into again criticizing Johnson's EU exit deal, as he did earlier this month on a London radio show hosted by Farage.

FILE - Leader of the Brexit Party Nigel Farage talks with a supporter during a general election campaign event in Seaham, Britain, Nov. 24, 2019.

During the program, which was on the eve of the official election campaign, Trump agreed with Farage, who wants a clean break from the EU, that Johnson's withdrawal agreement would make a trade agreement with the U.S. impossible.

"We want to do trade with the U.K. and they want to do trade with us. And to be honest with you, this deal, under certain aspects of the deal, you can't do it," Trump said.

According to a recent YouGov opinion poll only 18% of Britons hold a positive opinion of Trump,  so a fulsome endorsement of Johnson on his part wouldn't be helpful from the point of view of British Conservatives.

However, even foreign leaders who've been popular in Britain have discovered that remarks on domestic British politics can all too easily backfire, as former U.S. President Barack Obama found when he urged Britons to back staying in the EU in the 2016 Brexit referendum.

"The problem is it is impossible to predict what Trump is going to say," said a Conservative strategist, who asked not to be identified. "There's some anxiety about what he might say — or be tempted to say by reporters and opposition politicians out to provoke him — during the trip," he added.

Trump is scheduled to hold a press conference Wednesday before returning to Washington.