On the second day, the president gets down to work.
President Trump arrived in Britain on Monday for a welcome full of pageantry: an 82-gun salute at Buckingham Palace, a look at a collection of gifts with Queen Elizabeth II and a lavish banquet with members of the royal family.
On Tuesday, Mr. Trump’s schedule contains less pomp and more work.
He plans to attend a business round table at St. James’s Palace in the morning, followed by a meeting with Prime Minister Theresa May of Britain at her office at 10 Downing Street. Mr. Trump and Mrs. May are then scheduled to hold a joint news conference, and in the evening there will be a reception at the American ambassador’s residence.
Mr. Trump and Mrs. May are expected to discuss issues of security and trade, especially in the context of Brexit: Britain has hoped to strike a bilateral trade deal with the United States. It remains unclear what progress the two leaders might make, however, since Mrs. May is in the last days of her tenure in office, having agreed to step down as the leader of the Conservative Party after failing for almost three years to deliver Britain’s withdrawal from the European Union.
The president has criticized Mrs. May’s approach to Brexit before, and he has repeatedly praised the leading candidate to replace her, Boris Johnson. Before arriving in London, Mr. Trump suggested that he might meet with Mr. Johnson, the former foreign minister, calling him “a friend of mine.” He also suggested that he might meet with Nigel Farage, the leader of a pro-Brexit party.
“They’re two very good guys, very interesting people,” Mr. Trump told reporters last week.
Protesters have vowed to bring London to a standstill.
A giant orange balloon of President Trump, depicted as a scowling baby wearing a diaper, was to be released over Parliament Square in London on Tuesday, kicking off a day of protests against the president’s state visit to Britain.
The same large balloon was the focal point of protests that broke out during the president’s working visit last July, his first trip to Britain in office.
Mr. Trump is unpopular around Britain, and especially in London. He has feuded with the city’s mayor, Sadiq Khan, since 2016 over immigration, terrorism and other issues, and on Monday he belittled the mayor again, accusing him of being “nasty” and mocking his stature.
Large crowds of protesters, potentially numbering in the tens of thousands, are expected to gather in central London at 11 a.m. and march toward Downing Street, where Mr. Trump will meet with Prime Minister Theresa May and hold a news conference.
The demonstrators have vowed to disrupt every stage of Mr. Trump’s visit by bringing central London to a standstill. Last year Mr. Trump largely avoided London and the protests that erupted there.
“We are coming out in bigger numbers this time to deliver our message loud and clear,” said Amy Hunter, a protester and member of the Stop Trump campaign. “Trump and his racist, divisive policies are not welcome in our country.”
Mr. Trump and Mrs. May are expected to discuss Huawei and China.
When Prime Minister Theresa May and President Trump meet on Tuesday, they are widely expected to discuss Huawei, the Chinese company whose 5G technology has been the subject of warnings from Washington to its allies about what it considers to be serious security risks.
Britain’s foreign secretary, Jeremy Hunt, seemed to expect as much during an interview with the BBC on Monday. As he was waiting for Air Force One to land, Mr. Hunt said he and others were sensitive to Washington’s concerns. “We take careful notice of everything the U.S. says on these issues,” he said.
The Pentagon and American intelligence officials have warned allies that Huawei, which has been lobbying to build the next-generation network, could intercept or secretly divert secure messages to China. They have also warned that Huawei, because of the relationship between the authorities and businesses in China, could be ordered to shut down the networks during any conflict.
Last month, the Trump administration placed the company and dozens of affiliates on a list of firms deemed a risk to national security, a move that prevents it from buying American parts or technologies without first receiving approval from the United States government.
It also issued a separate order barring American telecom companies from using foreign-made equipment that could pose a threat to national security. Without naming Huawei, it meant Huawei.
Mr. Hunt was giving no hint about which way Britain would go. “We haven’t made our final decision,” he said. “But we have also made it clear that we are considering both the technical issues — how you make sure there isn’t a backdoor so that a third country could use 5G to spy on us — but also the strategic issues so that you make sure that you are not technologically overdependent on a third country for absolutely vital technology.”
Alan Yuhas, Ceylan Yeginsu and Christine Spolar contributed reporting.