Having watched the ceremony on her iPad, she was in no doubt that the marriage would have social consequences, which she welcomed. The 600 guests in St George's Chapel had comprised rich and poor, people of all races, she said, echoing the words of American Bishop Michael Curry, that all men are equal before God.
One day, she added, "we will all be the same colour, living happily together and not quarrelling."
She had been amused to see some of the female American guests wearing five-inch heels, presumably having not been told that Windsor had cobbled streets, but they had managed "very well".
The hats had impressed her too, and would no doubt be seen again at Ascot in a year or two, while the bride's gown had been suitably understated, "absolutely simple", lady-like and beautifully made.
"Heavy satin was perfect for her personality and complexion," Barbara said. And she had had the sense not to wear an elaborate necklace or earrings along with the diamond and pearl tiara lent to her by the Queen.
She did not entirely agree that the wedding was a modern day fairy tale though, in that Ms Markle had been very well educated and had always been ambitious and clever, making her own way in the world very successfully before meeting her prince.
"They are clearly very much in love with each other, and there was a nice family sort of feeling to the ceremony," she said, right down to Prince Harry accepting his bride from his father with the words, "Thanks Pa".
There was nostalgia for Barbara too, in the images of Windsor Great Park, where she was trained as a wartime ambulance driver in 1943. She had just completed that training when then Princess Elizabeth began hers.
"She did it properly too," she said. "She cleaned ambulances and changed oil — she could probably still strip a motor today if she wanted to."
