The US leader allegedly told a UK journalist that "200 years of history" can't be easily erased, while grumbling about Canadian politicians

US President Donald Trump allegedly conceded in private that Canada is unlikely to become part of the US, despite previously hinting at annexing the neighboring country, a snippet from an upcoming book by British journalist Robert Hardman has indicated.

Over the past year, Trump has on multiple occasions floated the idea of absorbing Canada as the 51st state and described its border with the US as "artificial." Canadian Prime Minister Mark Carney, in turn, has consistently stressed that "we will never, ever, in any way, shape, or form, be part of the United States."

On Sunday, the Daily Mail newspaper published an excerpt of Hardman's 'Elizabeth II. In Private. In Public. The Inside Story' - the journalist's sixth book on the British monarchy, due to be released later this week.

It features parts of Hardman's interview with Trump earlier this year, in which the journalist told the US president that a hypothetical annexation of Canada by the US would upset British King Charles III, who is also Canada's head of State.

This allegedly gave the US president pause, and he eventually acknowledged that the "Canadians have got 200 years of history and all that 'Oh, Canada' thing."

"You can't deal with that in three-and-a-half years. I guess it's not going to happen," Trump concluded, according to the excerpt.

"This was the closest I had heard to an acknowledgement that, as long as Canada had the King, Mr Trump was not going to usurp him," Hardman wrote in his book, as quoted by the Daily Mail.

Trump has publicly repeatedly expressed respect for the late British Queen and the British royal family in general.

Nevertheless, the US president did allegedly complain about "terrible" Canadian politicians, who are "nice to my face and then they say bad things behind my back."

Trump previously repeatedly claimed that the US was subsidizing Canada's economy to the tune of $200 billion a year, musing that it would be more feasible to absorb the country as the "cherished" 51st state.