I turn to glance at the massive reproduction of Sadie’s painting which is dominating the church. Around and beneath it are the most beautiful flower arrangements I’ve ever seen, with lilies and orchids and trailing ivy and even a reproduction of Sadie’s dragonfly necklace, made out of the palest yellow roses set on a bed of moss.

That one was done by Hawkes and Cox, which is a top London florist. They contacted me when they heard about the memorial service and offered to do it for free, because they were all such fans of Sadie and wanted to show their appreciation of her. (Or, to be more cynical, because they knew they’d get great publicity.)

I honestly didn’t intend this event to be such a massive deal at first. I just wanted to organize a memorial service for Sadie. But then Malcolm at the London Portrait Gallery heard about it. He suggested they announce the details of the service on their website for any art lovers who wanted to come and pay their respects to such a famous icon. To everyone’s astonishment, they were besieged by applications. In the end they had to do a ballot. It even made the London Tonight news. And here they all are, crammed in. Rows and rows of them. People who want to honor Sadie. When I arrived and saw the crowds, I actually felt a bit breathless.

“I’d also like to say, great clothes. Bravo.” I beam around at the vintage coats, the beaded scarves, the occasional pair of spats. “I think Sadie would have approved.”

The dress code for today is 1920s, and everyone has made a stab at it of some sort. And I don’t care if memorial services don’t usually have dress codes, like that vicar kept saying. Sadie would have loved it, and that’s what counts.

All the nurses from the Fairside Home have made a spectacular effort, both with themselves and also with all the elderly residents who have come. They’re in the most fabulous outfits, with headdresses and necklaces, every single one. I meet Ginny’s eye and she beams, giving an encouraging wave of her fan.

It was Ginny and a couple of other nurses from the home who came with me to Sadie’s private funeral and cremation, a few weeks ago. I only wanted people there who had known her. Really known her. It was very quiet and heartfelt, and afterward I took them all out for lunch and we cried and drank wine and told Sadie stories and laughed, and then I gave a big donation to the nursing home and they all started crying again.

Mum and Dad weren’t invited. But I think they kind of understood.

I glance at them, sitting in the front row. Mum is in a disastrous lilac drop-waisted dress with a headband, which looks more seventies ABBA than twenties. And Dad’s in a totally non-1920s outfit. It’s just a normal, modern single-breasted suit, with a silk spotted handkerchief in his top pocket. But I’ll forgive him, because he’s gazing up at me with such warmth and pride and affection.

“Those of you who only know Sadie as a girl in a portrait may wonder, who was the person behind the painting? Well, she was an amazing woman. She was sharp, funny, brave, outrageous… and she treated life as the most massive adventure. As you all know, she was muse to one of the famous painters of this century. She bewitched him. He never stopped loving her, nor she him. They were tragically separated by circumstances. But if he’d only lived longer… who knows?”

I pause for breath and glance at Mum and Dad, who are watching me, riveted. I practiced my whole speech for them last night, and Dad kept saying incredulously, “How do you know all this?” I had to start referring vaguely to “archives” and “old letters” just to keep him quiet.

“She was uncompromising and feisty. She had this knack of… making things happen. Both to her and to other people.” I sneak a tiny glance at Ed, sitting next to Mum, and he winks back at me. He knows this speech pretty well too.

“She lived ’til one hundred and five, which is quite an achievement.” I look around the audience to make sure everyone is listening. “But she would have hated it if this had defined her, if people just thought of her as ‘the hundred-and-five-year-old.’ Because inside, she was a twenty-three-year-old all her life. A girl who lived her life with sizzle. A girl who loved the Charleston, cocktails, shaking her booty in nightclubs and fountains, driving too fast, lipstick, smoking gaspers… and barney-mugging.”

I’m taking a chance that no one in the audience knows what barney-mugging means. Sure enough, they smile back politely, as though I’ve said she loved flower arranging.

“She loathed knitting,” I add, with emphasis. “That should go on the record. But she loved Grazia.” There’s a laugh around the church, which is good. I wanted there to be laughter.