The Queen works from her red boxes alongside a photo of her father and one of her beloved corgi dogs in an official photo released to mark her Platinum Jubilee.
She today marks 70 years on the throne - the first British monarch in history to mark the milestone.
The new photo shows the breaming Queen wearing a green dress with a pearl necklace and diamond brooch working through her government documents.
Her engagement ring from the Prince Philip is proudly on display, as is a photograph of her late father, King George VI.
On February 6, 1952, her father died suddenly at Sandringham making the then Princess Elizabeth the new monarch aged just 25.
Her 70-year reign has stretched from the post-war years through a new millennium and into a radically altered 21st century.
She has served as a symbol of stability as the world has changed in countless social, cultural, political and technological ways over the intervening decades.
The Queen was extremely close to her father, and one of her childhood friends said he set her a "wonderful example" for her time as monarch.
Anne Tennant, Lady Glenconner, who was a maid of honour at the Queen’s coronation, told BBC Radio 4’s Today programme the Queen would likely “look back very sadly” on the day as it also marked the death of her father, George VI.
She recalled being sent a letter by Margaret, the Countess of Snowden, describing the “beautiful Norfolk morning” on which the king had died at Sandringham.
“(It was) a beautiful Norfolk morning, sun coming out and all the geese and the birds flying over, and she said it was a sort of perfect morning that her father would have loved and it was so wonderful that he had died in Norfolk, his beloved Norfolk, on such a beautiful day,” Lady Glenconner said.
She described the “moving” moment she watched Elizabeth on television returning from Africa with the knowledge she was to become Queen.
“It’s so moving, standing at the top of the stairs in her black coat. And suddenly, somebody that we’d known, I’d known, since she was a child, was Queen.
“She was a very slight figure and she was very young but I felt that she had, from a very young age really, she knew she was going to be Queen. I think her father was a wonderful example to her because he put his every duty first.”
Asked whether the anniversary would be tinged with sadness for the monarch as it was also linked to her father’s death, Lady Glenconner said: “I think the Queen will look back very sadly.”
She added: “I think it means a lot to her. She’s a countrywoman too, the Queen.”
Last night, the Queen released a statement to mark the occasion - thanking well-wishers for their support and confirming she wants her daughter-in-law, Camilla, to become Queen Consort when Charles takes the throne.
She wrote: "It is a day that, even after 70 years, I still remember as much for the death of my father, King George VI, as for the start of my reign.
"As we mark this anniversary, it gives me pleasure to renew to you the pledge I gave in 1947 that my life will always be devoted to your service.
"As I look ahead with a sense of hope and optimism to the year of my Platinum Jubilee, I am reminded of how much we can be thankful for. These last seven decades have seen extraordinary progress socially, technologically and culturally that have benefitted us all; and I am confident that the future will offer similar opportunities to us and especially to the younger generations in the United Kingdom and throughout the Commonwealth.
"I am fortunate to have had the steadfast and loving support of my family. I was blessed that in Prince Philip I had a partner willing to carry out the role of consort and unselfishly make the sacrifices that go with it. It is a role I saw my own mother perform during my father’s reign."
Earlier this week she shared photos of her looking through cards and gifts sent from well-wishers to celebrate the Jubilee, with a little help from her dog Candy.
People around the world have paid tribute to the Queen's today, sending messages to congratulate her on the unprecedented achievement.
Her eldest son, Prince Charles, said: " On this historic day, my wife and I join you all in congratulating Her Majesty The Queen on the remarkable achievement of serving this nation, the realms and Commonwealth for seventy years.
“The Queen’s devotion to the welfare of all her people inspires still greater admiration with each passing year.
“We are deeply conscious of the honour represented by my mother’s wish.
“As we have sought together to serve and support Her Majesty and the people of our communities, my darling wife has been my own steadfast support throughout.
“The year of this unprecedented Platinum Jubilee brings an opportunity for us all to come together in celebrating the service of The Queen, by whose example we will continue to be led in the years to come.”
Labour leader Sir Keir Starmer said: “Her Majesty The Queen has been one vital and valued constant in an ever-changing world, representing security and stability for our country, during the ups and downs of the last seven decades.
"While today’s date will always be one of sadness for Her Majesty, as she remembers her beloved father King George VI, it is a chance for the rest of us to express our gratitude for a life of unprecedented dedication to duty and commitment to our country.
"On behalf of the Labour Party, I would like to express my deepest thanks to Her Majesty for seven decades of unparalleled public service.
"Her Majesty is a global symbol of grace and dignity and we thank her from the bottom of our hearts for her 70 years of selflessness and service as we celebrate Her Majesty The Queen’s Platinum Jubilee."
