Not until the end, when tears had been shed almost solidly for an hour at Westminster Abbey, did the full scale of the loss show itself in a seemingly never-ending procession of sadness.
Children holding the hands of now-single parents; the elderly being propped up by their son or daughter's widowed partner; brothers, sisters looking fractured in their sorrow. This is how they marched out and, like a great river of grief, they took 19 minutes to pass.
The old Abbey has seen good times and bad but, as a memorial to murder on a grand scale, there had been nothing like this.
They came in their hundreds, not just to pray for the 76 Britons who died on 11 September – although that was the reason for the gathering – but to remember those of all nationalities who had perished. Even those innocents still dying in Afghanistan.
There had been a similar memorial service for Britons at St Thomas's Church in New York shortly after the attack on the World Trade Centre, but that was different. This was like coming home.
Home, even, for those who lived in America. Like seven-year-old Caileigh Maddison, her four-year-old brother, Kyle, and 16-month-old sister, Sydney, who came with their American mother, Maureen, to mourn their Essex-born father, Simon.
They stood at the great west gate of the Abbey, shuffling nervously in the cold, waiting to be presented to the Queen. A meeting with the Queen, they had told their mother, would show just how important their Daddy was. So it was that they came to hand over to the sovereign a posy of white bianca roses, for peace and friendship, and lilies of the valley, nature's promise of hope and happiness.
Mr Maddison, 40, a freelance computer programmer from Harlow, was just one of the many unfortunates being remembered. He had been working on the 103rd floor of the north tower when disaster struck. A devoted family man, he had left home before 6am on the day without waking his wife so that he could come home early to play with the children.
When Caileigh handed over her posy to the Queen with a slight curtsy, there was no outward sign of the pain she and her whole family were feeling, the same kind of pain being endured many times over by those assembled in the Abbey.
As Mrs Maddison put it: "Caileigh told me that when she misses Daddy, she thinks of something funny that he used to do – like making the children into a sandwich on the bed, using pillows as bread and Caileigh and Kyle as cheese and tomato. Sydney only played once, but she was the ham.
"[Kyle] still opens his window at night to send his daddy hugs and kisses. One night, Sydney woke up crying and led me with her finger to Daddy's picture on the refrigerator door. Her first word was 'Daddy'. It will be great to be able to tell her that when she gets older.
"We had eight years together, but it was too short. I miss him terribly but I hear him in my head all the time and I know he wouldn't want me to be so sad. When I see the children doing something special, I feel angry that he was robbed of the chance to be there and see them grow up and that he can't be there for them."
In spite of the children's confusion, Mr Maddison's father, Peter, 75, is justly proud of his eldest granddaughter. "When the bombing of Afghanistan started, the first thing that Caileigh said was that she hoped people wouldn't get hurt," he said.
For Caileigh, meeting the Queen added to an unforgettable occasion. "I was a little nervous but also excited," she said. "I was glad we did it. I was thinking about Daddy and I was thinking about him watching us."
After the young Maddisons had handed their posy to the Queen, the service began. The Prime Minister and his wife, Cherie, were there, with representatives of the other main parties. The Queen was accompanied by Prince Philip and the Prince of Wales, while as a sign of respect from America, the former president George Bush Snr attended with the US ambassador, William Farish, and representatives of the police and fire departments of New York.
Almost from the beginning, the broad north and south transepts of the Abbey, where the bereaved had been seated, echoed softly with the sound of weeping.
Dr George Carey, the Archbishop of Canterbury, was unequivocal in his condemnation of the men who had caused such grief. "Those who claimed to be serving God by such appalling and indiscriminate bloodshed are cruelly deceived," he said. "They besmirch the very basis of true faith." While condemning the atrocities in the US, the Archbishop was anxious also to call upon rich countries to help the poorer states so that the injustices that bred terrorism could be eradicated.
When the service was over, the bereaved were invited to follow the Queen in laying a white rose each on the Abbey's Memorial to Innocent Victims outside, a white circular sculpture by the Irish artist Ken Thompson. It reads: "Remember all victims of oppression, violence, war."
The journey there, down the Abbey's well-trod aisle, seemed long and hard. It was clear that there were too many old people outlasting their children, and too many young ones who will perhaps one day find it hard to remember a father or mother.
Outside, the rain made it difficult to take away anything uplifting from the ceremony. But many will have taken comfort from Christina Rossetti's poem, Remember, read by Dame Judi Dench. Opening, "Remember me when I am gone away..." it concludes: "Yet if you should forget me for a while/ And afterwards remember, do not grieve/ For if the darkness and corruption leave/ A vestige of the thoughts that I once had/ Better by far you should forget and smile/ Than that you should remember and be sad."