The queen will ride on a steam train in Scotland to inaugurate a new railway line and will host a dinner at Balmoral Castle with her grandson Prince William and his wife Kate in attendance.
According to calculations by royal officials, at around 1630 GMT Elizabeth will beat her great-great grandmother Victoria’s time on the throne: a total of 63 years, seven months and two days which she served between 1837 and 1901.
The exact hour has been difficult to determine because the exact start of her reign — the moment when her father George VI passed away — is difficult to work out as the king died at night in his sleep.
The 89-year-old Elizabeth, also the world’s oldest monarch, had originally not planned anything special for the day itself but reportedly agreed to a public appearance due to public pressure.
“You need to remember for the queen this is a date whose calculation rests on the death of her father and great-great grandmother. That naturally colours the way she sees it,” a royal source said.
“While she acknowledges it as an historic moment, it’s also for her not a moment she would personally celebrate, which is why she has been keen to convey business as usual, and no fuss,” the source said.
Buckingham Palace will mark the day with a photo display of her reign and the Royal Mint has designed a new silver £20 coin (27 euros, $30) with the five official portraits since she became queen in 1952.
Queen Elizabeth II’s reign in figures
Queen Elizabeth II will on Wednesday pass the landmark for longest-reigning monarch set by Queen Victoria. Here are some figures about her reign, which has lasted more than 63 years:
– 33,446,430 minutes or 23,226 days, 16 hours and 30 minutes is the amount of time the queen will have spent on the throne when she breaks the record on September 9 at roughly 5:30 pm (1630 GMT).
– 12 prime ministers have been in power during her reign. The first was Winston Churchill, who mentored her when she first took the throne aged 25 in 1952, and the most recent is David Cameron.
– 10 hours spent delivering her 62 Queen’s Speeches, delivered at the state opening of parliament and written for her by the government of the day to outline its legislative plans.
– 56 Christmas messages delivered to the nation. It is a ritual for many British families to sit and watch the queen’s festive message on television after eating their Christmas lunch.
– 97 state visits, the first to Norway in 1955 and the most recent to Germany in June. Despite her extensive travels, the queen does not possess a passport.
– 50,000 people on average are invited every year to garden parties, dinners and other events hosted by the queen.
– 67 years of marriage to Prince Philip whom she has called “my strength and stay”. The couple were married on November 20, 1947.
– The world’s longest-serving living monarch is Thailand’s King Bhumibol Adulyadej, who has reigned for six years longer than the queen.