Charles III will deliver the first King's Speech in over 70 years, formally inaugurating the UK parliament and presenting the government's legislative agenda as an election looms.
The 74-year-old monarch will outline the legislative priorities of Conservative Prime Minister Rishi Sunak, highlighting the differences between his government and the main opposition Labour Party.
Delivered from a golden throne in the House of Lords, this address comes as the Tories, who have been in power since 2010, lag behind Labour by double-digits in most opinion polls ahead of an election expected next year.
"The King's Speech represents one of the last opportunities for Rishi Sunak to present his agenda," said Richard Carr, an associate professor in public policy and strategy at Anglia Ruskin University.
"As a low-polling prime minister, one of the few advantages he currently possesses is the ability to set the national agenda, control the content published in supportive newspapers, and create obstacles for the opposition," he told AFP.
This ceremonial address and the accompanying traditions mark Charles's first as monarch, although he had a practice run as a substitute for Queen Elizabeth II in May last year.
It's also Sunak's first since taking over from Liz Truss, who succeeded Boris Johnson as prime minister just two days before the queen's passing and lasted only 49 days in office.
In the speech, Sunak will emphasize the clear distinctions he is making with Keir Starmer's centre-left Labour party on issues related to the environment and energy.
He is expected to propose a law that grants new licenses for annual oil and gas projects in the North Sea, which he believes will reduce the UK's dependence on foreign energy and generate employment.
In September, Sunak had already announced a rollback of green energy policies, positioning himself as a champion of motorists in an effort to reverse his party's declining fortunes.
In contrast, Labour has stated that it will not issue new oil and gas exploration licenses and has committed to increasing investments in green energy.
Sunak's proposals may pose a challenge for Charles, who has been a lifelong advocate for environmental causes.
The King's Speech, expected to last about 10 minutes, will also introduce stricter sentencing guidelines for life terms and the elimination of early release for certain violent sexual offenders.
Sunak is likely to include a phased smoking ban, announced at last month's Tory conference, and reforms to property ownership laws.
The King's Speech marks the beginning of a new parliamentary year and was last delivered by a male monarch in 1951, albeit not in person, as King George VI was unwell. It outlines the types of legislation the government aims to pass in the next 12 months.
While a Tory defeat in the upcoming election is not guaranteed, given their substantial parliamentary majority, losing would likely result in much of the proposed legislation not being enacted.
"The problem for Sunak is that he's running out of time, and the public is both bored and frustrated with Conservative governance," Carr added.
The state opening on Tuesday traditionally involves the monarch traveling by carriage from Buckingham Palace to the Houses of Parliament.
An MP is symbolically held as a "hostage" to ensure the king's safe return.
Royal bodyguards conduct a ritual search of the basement of the Palace of Westminster for explosives, a legacy of the failed attempt by Catholics to blow up parliament in 1605.
The monarch leads a procession through the House of Lords, the unelected upper chamber of parliament, before delivering the speech to assembled lords and ladies, along with invited members of the elected lower House of Commons. Photo by University of Essex, Wikimedia commons.