The King celebrates his 75th birthday on Tuesday, just over a year after acceding to the throne.

The monarch, who is 14 months into his job as head of state, reaches his three-quarter century milestone in the same year he was crowned, and a week after opening Parliament for the first time as sovereign.

Charles, who will still receive his daily red boxes full of policy papers, Foreign Office messages, letters and other state papers on his big day, will also spend his anniversary carrying out public engagements.

He will use his significant birthday to highlight causes close to his heart.

The King, who is appearing on the front cover of this week’s Big Issue, will visit a surplus food distribution centre with the Queen to officially launch the Coronation Food Project, which aims to tackle food poverty by redistributing produce destined for landfills.

And later he will host a reception at Buckingham Palace for 400 nurses and midwives, as part of this year’s NHS 75 celebrations, and be treated to a surprise birthday song by the NHS choir.

Gun salutes will sound in Green Park and the Tower of London in the capital, and across the UK.

Camilla once revealed the King is particularly hard to buy gifts for.

“I will tell you that he is the most difficult person in the world to buy a present for … So he likes to make a list of things that he wants so you get it exactly right,” she said.

He likes “a cake and a bit of a sing song”, she acknowledged, but admitted it was difficult to get her workaholic husband to take break.

In the evening, Charles’s nearest and dearest are expected to gather at Clarence House for a birthday dinner in his honour.

But his youngest son the Duke of Sussex and the Duchess of Sussex will be missing.

It was reported Harry turned down an invitation, but the Sussexes’ team has insisted they did not receive one.

The duke’s relationship with the King and brother Prince of Wales has remained fractured in the wake of his controversial Netflix documentary and autobiography Spare.

A spokesperson for the Sussexes said: “In response to UK media headlines, there has been no contact regarding an invitation to His Majesty’s upcoming birthday.”

The King will spend this Remembrance Sunday leading the nation in tribute to the war dead at the Cenotaph on Whitehall, joined by the Queen, the Prince and Princess of Wales and other royals.

On Monday – the eve of his birthday – he will celebrate with fellow baby-boomer 75-year-olds at an afternoon tea birthday party with live rock music and dancing at his Gloucestershire retreat Highgrove.

The event is being staged for nominated community heroes and those seeking to socialise, who like the King were also born in 1948.

It will mark as well the 75th anniversaries of the NHS and the Windrush generation.

TV star Jay Blades, who bonded with the King over a shared interest in heritage and crafts in an episode of the BBC’s The Repair Shop, will be there as an ambassador for Charles’s freshly renamed charity, The King’s Foundation, formerly The Prince’s Foundation, which is hosting the day.

Prince Charles Philip Arthur George was born on November 14 1948 at Buckingham Palace – the first child of the future Queen Elizabeth II and the Duke of Edinburgh.

He was 73 when he acceded to the throne as Charles III immediately on the death of Elizabeth II, who died peacefully at the age of 96 in the sanctuary of Balmoral Castle on the afternoon of September 8 2022.

Charles is the oldest British monarch on accession.

When he turned 70 in 2018, he referred to his birthday as “alarming” and joked he had “all the scars that go with” his age.

As well as his coronation in May, Charles has had a busy 2023, with three overseas state visits to Germany, France and Kenya and, earlier this week, his first State Opening of Parliament as monarch.

As King, Charles now has two birthdays – his actual birthday on November 14, and his official one, usually on the second Saturday in June, commemorated with the Trooping the Colour parade.