The nation's most celebrated centenarian enjoyed a quiet day with family and friends yesterday: up late, visit from the postman, picked up by grandson and driven round the corner for lunch at her daughter's.
Being the Queen Mother, she was accompanied by two military bands and a mounted cavalry escort from the Blues and Royals, and received a 41 gun salute.
Waving to acknowledge the greetings of a crowd in the Mall, the first member of the royal family to reach her 100th birthday looked in robust and cheerful good health.
As the sun came out, and the time for her parade approached, numbers swelled to fill the area in front of Buckingham Palace to respectable if not ecstatic dimensions, probably in excess of 30,000. Many were tourists from abroad, pleased to see the daily spectacle of changing the guard supplemented by a royal pageant.
When the Queen Mother appeared on the balcony of the Buckingham Palace, accompanied by her daughters and then gradually the rest of the royal family, while the band of the Coldstream Guards below played Happy Birthday, there was a surge of cheering and applause.
The first public appearance came at mid-morning outside the Queen Mother's residence, Clarence House, with the arrival of the royal postman, Tony Nicholls. Moments earlier he had driven self-consciously up the Mall in his little red van in the wake of the gun carriages of the Royal Horse Artillery and a troop of Life Guards.
The card from the Queen he delivered was the same she sends all centenarians (including 11 others who had birthdays yesterday), but it had a personalised message. The Queen Mother handed the envelope to an equerry, Captain William de Rouet, with a request for him to use his sword as a letter opener.
Proving that - like the rest of us - the Queen has difficulty finding something novel to write in birthday cards, it read: "On your 100th birthday all the family join with me in sending you our loving best wishes for this special day." But it was signed with the pet name by which the Queen, herself 74, was known as a child, Lilibet.
For the short journey up the Mall, the Queen Mother was joined by her grandson, the Prince of Wales, in an open-topped landau, drawn by four grey horses and decorated in her racing colours. Back at Clarence House, five ladies in waiting were deputed for an hour to continue to accept gifts and cards.
The procession wound down into the Mall, past the Victoria Memorial with its statue of a world-weary queen who still had five months to live when the Queen Mother was born. As the carriage drew through the main gates of Buckingham Palace the waiting band struck up the national anthem.
Then, in the hiatus after the party disappeared inside, the police formed up like defenders in front of a goal mouth, to protect the open gates from the surging crowd, while in the courtyard the band surreally moved into a medley including the Grandstand theme and Blaydon Races.
Right on cue, the ageing trouper appeared to acknowledge the cheers. Down in the crowd, the sentiment was that she was wonderful. Myra Roger, her daughter Ruth Franton and grand daughters Jennifer and Kirsty, up for the day from Beaconsfield in Buckinghamshire, were enjoying every moment.
"It's a momentous historical occasion," said Myra. "She represents old fashioned virtue - the epitome of the royal family. She's not changed for the worst, has she?" Further along, Sally Marchant from Carshalton in south London, and her sister Maureen Boyd, home on holiday from Australia, reckoned they knew the secret of the Queen Mother's success: "She's a great figurehead for royalty, isn't she? I think she advises quietly behind the scenes, don't you? She keeps them in line."
Katie Miller, aged seven, of Chorleywood in Hertfordshire, thought the Queen Mother looked lovely. "I don't think she looks 100. I think she looks more like 82. I want to come back when the Queen's 100," she said.
The band in the courtyard played on, Jerusalem and Who's Your Lady Friend? Over the heads of the departing crowd came the sound of street vendors making a last effort: "Any more for flags?"