Smiling continually, waving, and more emotional than the public has ever seen her, the Queen pulled up in her State Bentley at the West Steps of St Paul's Cathedral for a service of thanksgiving.
A congregation of 2,000 had gathered to give thanks for her "loyal service and commitment" in a glorious reign that has, for six decades, been a beacon of stability and hope in an ever-changing world.
Elizabeth II is only the second monarch after Queen Victoria to celebrate 60 years on the British throne. When Victoria marked her Diamond Jubilee, aged 78, she was too frail to climb the 24 steps to the great cathedral, so the service was held outside.
No such problem more than a century later for her great-great-granddaughter, whose stamina impresses, even at eight years older.
Accompanied by 40 members of her family, the monarch – shimmering in a mint green Angela Kelly creation – listened as the Archbishop of Canterbury paid tribute to her.
He told those gathered: "What we remember is the simple statement of commitment made by a very young woman, away from home, suddenly and devastatingly bereaved, a statement that she would be there for those she governed, that she was dedicating herself to them.
"I don’t think it’s at all fanciful to say that, in all her public engagements, our Queen has shown a quality of joy in the happiness of others.
"She has made her public happy. And all the signs are she is happy, fulfilled and at home in these encounters."
The only sadness during this celebration is that her beloved husband Prince Philip was absent after he was treated in hospital for a minor infection.
During 64 devoted years of marriage, he has shared all the joys and sorrows of her life.
Various alterations were made to the arrangements after Philip was taken to hospital. The seating plan was changed to put the matriarch next to her heir Prince Charles, rather than at the very front on her own.
And accompanying the sovereign on the journey to the service was her lady-in-waiting, Diana, Lady Farnham.
She cut something of a solitary figure, however, without her strength and stay at her side during the procession through the nave.
And more than once this most reserved of women, looked wistful, a little overwhelmed even.
Putting the emphasis on the future of monarchy, she was preceeded by those who will continue her life's work, including her son and his wife the Duchess of Cornwall, Prince William and the Duchess of Cambridge, and Prince Harry.
The Archbishop of Canterbury refered to the absent Duke, saying "our prayers and thoughts are very much with him this morning".
Philip was by her side ten years ago on the occasion of her Golden Jubilee when the royal matriarch told the nation: "Gratitude, respect and pride, these words sum up how I feel about the people of this country and the Commonwealth".
Much has changed since then. Britain is more multi-cultural than ever and has experienced three different prime ministers and had a change of government.
Meanwhile, the British monarchy has moved with the times, embracing social networks and YouTube. And thanks to the wedding of the Cambridges, their popularity is at an all time high.
But Her Majesty's values and dedication to service remain the same.
Thrust onto the world stage aged 25 in 1952, she promised to serve her country for the rest of her life – a vow that is the central priority in her life even now.
Now, aged 85 she is a proud grandmother eight times over, with another two great-grandchildren as well.
But any suggestions of retirement were banished by her promise to re-dedicate herself to the nation on the anniversary of her accession – the date of her father King George VI's death on February 6, 1952.
And they were far from everyone's mind as the 75-minute ceremony began with a bidding delivered by The Very Reverend David Ison, the Dean of St Paul's.
He gave thanks for the Queen's "loyal service and commitment" and celebrated "the identity and variety which our nations under her have enjoyed" before leading the congregation in the Lord's Prayer.
The service was a religious celebration of the life of the monarch, who is head of the Church of England, and is said never to have missed a Sunday service in her whole life.
There was an Old Testament reading, from Proverbs, extolling the wisdom of God, while the New Testament reading – delivered by Prime Minister David Cameron – returned to the theme of duty and sacrifice.
It included the words: "Let love be genuine; hate what is evil, hold fast to what is good; love one another with mutual affection; outdo one another in showing honour."
Tthe service continued with prayers read by inspirational young people, including top scout Caitlin Ripley and Birmingham-born single mum Naomi Spencer.
Naomi, Ambassador of the Year for The Prince's Trust, a charity founded by Prince Charles, spoke exclusively to HELLO! Online about her excitement at the invitation to take part.
The service drew to a close with The National Anthem.
Key timings for final day of Jubilee celebrations
- 10.15am: Her Majesty leaves Buckingham Palace by car for St Paul's Cathedral
- 11.30am: The Queen will travel from the Cathedral to Mansion House via St Paul's Churchyard, Queen Victoria Street, and into the Walbrook Entrance
- 11.35am: The Queen arrives
- 12.30pm: The Queen departs from Mansion House and heads for Westminster Hall for Diamond Jubilee Lunch
- 12.40pm: The Queen arrives at Westminster Hall
- 12.45pm: The Queen and close royal family will be led into Westminster Hall via the South steps, as a Fanfare is sounded by the State Trumpeteers
- 2.20pm: The Queen, Prince of Wales, Duchess of Cornwall, Duke and Duchess of Cambridge and Prince Harry will depart for Buckingham Palace in a carriage procession
- 2.40pm: The carriage procession will arrive at Buckingham Palace
- 3.30pm: The Royal family will appear on the balcony of the palace to watch a flypast and Feu de Joie
As the cathedral reverberated with the sound of 2,000 voices proclaiming "God save the Queen", the monarch may have cast her mind back to June 2, 1953.
This was her coronation day, held more than a year after the death of her father as a mark of respect.
Back then, St Edward's Crown was placed upon her head in Westminster Abbey, and she was crowned Queen of the United Kingdom, Canada, Australia, New Zealand, South Africa, Ceylon, and Pakistan, as well as taking on the role of Head of the Commonwealth.
After the final note was sung on Tuesday the Queen – the second longest-serving living monarch in the world after Thailand's King Bhumibol Adulyadej – left to the strains of Orb and Sceptre, a march created specially for her coronation.
Walking ahead of her was the Lord Mayor bearing the Pearl Sword, which legend suggests was given to city of London by the first great Queen Elizabeth in 1571, and which takes its name from its scabbard of pearls.
Then, the Queen departed once more to greet the hundreds of thousands outside. And seeing that famous wave those she has served for six decades responded joyfully, as if with one voice.
Reporting by: Ian Cowley, Mulenga Hornsby, Katherine Robinson, Gemma Strong, Alexandra Light, Andrea Caamaño, Andrea Maltman, Tom Burgess, Amy Hillier
Thanksgiving Service Guest List
Inspirational members of the community:
Jemma Samuel, National Cadet of the Year, St John's Ambulance
The Lord Shuttleworth, KCVO, Lord-Lieutenant of Lancashire
Able Cadet Hannah Subit, Beckenham and Dulwich Unit, Sea Cadet Corps
Samuel Odusina, Gold Award Participant, Duke of Edinburgh's Award
Naomi Spencer, Young Ambassador of the Year, The Prince's Trust
Caitlin Ripley, Queen's Scout
Captain Giles R Sugdon, RLC, The Queen's Own Gurkha Logistic Regiment
40 members of the Royal Family including:
Duke of Edinburgh
Prince of Wales and Duchess of Cornwall
Duke and Duchess of Cambridge
Queen's staff and friends
Rt Hon Christopher Geidt, Her Majesty's Private Secretary
Lord Janvrin, Her Majesty's former Private Secretary
Angela Kelly, Her Majesty's Personal Assistant and Senior Dresser
Margaret Rhodes, close friend and cousin of the Queen
The Ladies-in-Waiting; Lady Susan Hussey, Duchess of Grafton, Countess of Airlie,
Representatives of Her Majesty's Patronages, from:
Sue Ryder Care
The Royal College of Veterinary Surgeons
Golf Union of Wales
Amateur Swimming Association
The Scout Association
The Shire Horse Association
Royal Shakespeare Theatre
Royal Northern College of Music
The Boys' Brigade
David Cameron, Prime Minister and Conservative Party Leader
Nick Clegg, Liberal Democrat Party Leader
Ed Miliband, Labour Party Leader
Gordon Brown, Former Labour Party Leader
Tony Blair, Former Labour Party Leader
John Major, Former Conservative Party Leader
His Excellency Kamalesh Sharma, Commonwealth Secretary-General