The Queen is set to enter the milestone 70th year of her reign, as she prepares to mark the anniversary of her accession away from Sandringham for the first time in more than 30 years.

Elizabeth II – the nation’s longest reigning monarch – will reach 69 years on the throne on February 6, meaning she is just one year away from her Platinum Jubilee.

The coronavirus pandemic has forced a break in the Queen’s long-held personal tradition of reflecting on the sad anniversary of her father’s death and the start of her reign at Sandringham House in Norfolk.

Instead, the monarch, 94, will be at Windsor Castle, where she and the 99-year-old Duke of Edinburgh are spending lockdown, looked after by a reduced household of staff dubbed HMS Bubble.

It was at Sandringham that King George VI died peacefully in his sleep early on the morning of February 6, 1952, after suffering from lung cancer.

Princess Elizabeth, then just 25, was away in Kenya on a Commonwealth tour, and returned home as monarch.

The Queen is last believed to have been away from Sandringham for her accession anniversary 31 years ago in 1990 while on an official visit to New Zealand.

Lengthy Commonwealth tours in the 1950s and the 1960s also occasionally meant the Queen was out of the country during February.

The Queen was in Australia when she reached two years on the throne, carrying out an epic six-month Commonwealth tour from November 1953 to May 1954.

In the Silver Jubilee year of 1977, the Queen and the royal family gathered at the Royal Chapel in Windsor Great Park for a service to commemorate the 25th anniversary of her accession.

Joe Little, managing editor of Majesty magazine, said: “It would seem to be 31 years since the Queen wasn’t at Sandringham on Accession Day.

“She likes to spend the day quietly in reflection on the passing of her father so it’s certainly not a day to celebrate, which is why the big Jubilee milestones take place in the summer, partly because of the weather, but also because it would not be appropriate.”

Mr Little suggested: “Given the passage of time and that this is now 69 years since her father died, the poignancy must have dissipated a bit.

“It’s less of a tug on the heartstrings than it would have been in the early years of her reign.

“But clearly, it is a very important day for her and it always will be. ”

Mr Little said the Queen would usually be visited by a vicar at Sandringham for private prayers in memory of her father, and suggested the tradition might be followed at Windsor this year in the Castle’s private chapel.

“I think whatever she does privately by way of commemoration at Sandringham will be transferred to HMS Bubble and that it will take place there, but I’m sure it will be an incredibly low key thing,” he said.

“It might just be her and a member of the clergy saying a few prayers in memory of the King and maybe the Queen Mother as well.”

The Queen would also have the option this year of visiting her parents’ tomb in the King George VI Memorial Chapel within St George’s Chapel in the grounds of Windsor.

In England, churches are allowed to remain open, in a Covid-secure way, for individual prayer and public worship.

Buckingham Palace has not commented on the Queen’s plans.

The Queen has been a figure of continuity as her country has changed through the 20th century, the Millennium and into the 21st century amid new technological and social advances and a succession of British governments.

She reached her Silver Jubilee in 1977, Golden one in 2002 and Diamond Jubilee in 2012, and overtook Queen Victoria as the nation’s longest reigning sovereign in 2015.

The public has looked to the Queen in times of tragedy – the September 11 terror attacks, the London bombings, the death of Diana, Princess of Wales, and more recently during the coronavirus crisis.

But even she confessed of the global Covid-19 pandemic: “While we have faced challenges before, this one is different.”

On how the monarch is spending her time during lockdown, Mr Little suggested that, although the head of state has her staff and the company of Philip, it is perhaps one of the “most isolated periods” of her reign.

“It must be quite a solitary existence because I don’t imagine that she and the duke are in each other’s pockets all day, every day,” he said.

“I’m sure they overlap for lunch and dinner perhaps but the rest of the time they must presumably be off doing their own things.”

He added: “It seems to be one of the most isolated periods of the Queen’s reign, or life really, because she can’t see her friends, she can’t see her family.”

The Queen’s accession anniversary also comes as the monarch is mourning her former Master of the Horse Lord Vestey, who was part of her inner circle of friends, and whose death was announced on Thursday.

The Queen, who stayed at Windsor for Christmas for the first time in decades, would usually spend her entire winter break at Sandringham.

“At Sandringham, if she were still there, she would be entertaining. There would be house parties and there would be family coming and going but none of those rules can apply at the moment, ” Mr Little said.

“It must impact on her in the way that it’s impacting on so many others but to a less dramatic extent.”

This year, the Queen is set to turn 95 in April, while Philip’s 100th birthday is in June.

Next year, the public will get an extra day off as part of a four-day weekend of Platinum Jubilee celebrations from June 2-5.