King Charles's upcoming speech before the Canadian parliament has sparked fear of causing offence to US President Donald Trump among some in the British government.

The 76-year-old monarch will travel to Canada, where he serves as head of state, to open that nation’s parliament.

The King will deliver the "speech from the throne" in Ottawa on Tuesday, a ceremonial role last performed by his mother, Queen Elizabeth II, in 1957.

However, Charles’s visit comes at a time of geopolitical tension between Canada and the United States - which has prompted anxiety among some in London.

Charles will balance a tricky geopolitical relationship between Canada and the US during his trip.

“British ministers have been trying to persuade the Canadian government to keep Charles free of any controversy around Donald Trump,” a Commonwealth source looped in on discussions revealed to The Times.

However, the insider added that attempts have been “fiercely resisted” by Ottawa.

Canada’s relationship with the United States has been a rocky one since Donald Trump was re-elected last year.

The maverick US president has slapped his northern neighbour with a series of punishing trade tariffs and has repeatedly vowed to make them the 51st US state.

Elements of the British government are concerned about antagonising President Trump with the visit.

Canada’s Prime Minister, Mark Carney, the former Bank of England governor, rode a wave of anti-Trump sentiment to win a stunning election victory in April.

Most of King Charles’s speech before the parliament in Ottawa will be written on the advice of Canada's government, which experts expect to see coded references to their stand against Trump.

“There will be a strong subtext, and the Canadians are very keen to see that,” Professor Philip Murphy, director of history and policy at the University of London, told The Times.

Murphy expected that Ottawa may try “exploiting the ambiguities” of Charles’ role as constitutional monarch of both Britain and Canada.

Canada is keen to use the occasion to stress their resistance to US pressure.

"By having him there they can stress that the UK is on Canada’s side in any trade confrontation with the US,” he explained.

Prime Minister Carney, 60, who recently clashed with Trump at the White House meeting recently, declaring that his country “won’t be for sale, ever”.

The PM explained to Sky News that his invitation to Charles and Camilla was “not coincidental” and “a clear message of sovereignty”.

Jeremy Kinsman, former Canadian high commissioner to the UK, observed: “This is a big deal for the King to do this.”

Charles will also have the opportunity for personal remarks within his speech.

However, he added that he hopes Trump “understands” the nuances necessary in such a delicate matter.

Kinsman expected that Charles’ speech will be "very affirmative of Canadian sovereignty" which he the monarch will “celebrate”.

The King's speech will be delivered in both French and English, reflecting Canada's bilingual heritage. It will primarily outline the government's legislative plans, but Kinsman predicts it will emphasise that "Canada will not be the US 51st state."

"It will say the government will protect, pursue and preserve the sovereignty of Canada as an independent state," Kinsman forecasted.

While most of the speech will be written on the advice of Canada's government, there is precedent for personal remarks. Queen Elizabeth II began her 1977 throne speech with her own comments, suggesting King Charles may add personal thoughts.