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The Queen has an "encyclopaedic" knowledge of every horse she has ever bred for racing, her daughter-in-law has said.
Camilla, the Duchess of Cornwall, said horse racing was the Queen's "passion in life", as she spoke ahead of 2021's Royal Ascot, which the monarch is hoping to attend.
The Queen, 95, avoided day one of Ascot but is said to be hopeful of going later in the week.
The annual horse racing event is one of the government's pilot events for a return to mass gatherings, and several members of the Royal Family are at day one in Berkshire.
Before the event, Camilla told ITV of the Queen: "Well, I think this is her passion in life and she loves it, and you can tell how much she loves it.
"She could tell you every horse she’s bred and owned from the very beginning – she doesn’t forget anything. I can hardly remember what I bred a year ago but she’s encyclopaedic about her knowledge."
Asked about Royal Ascot, she said: "Everybody who loves racing, it is the most special week, isn’t it?"
John Warren, the Queen's horse racing manager, told Radio 4: "Obviously the Queen would love to attend, as you know she’s fanatic about racing, watching racing and breeding horses, and has been going to Ascot all of her adult life.
"So, it’s a shame to miss an event.
"The plan at the moment is to see how it goes towards the latter part of the week and if the Queen’s able to come because she’s got runners, then, fingers crossed, it will happen."
There will not be a traditional carriage procession if she does attend. Her son Prince Charles, and Camilla, arrived in a car on day one, with Camilla wearing a cream and blue dress by Bruce Oldfield and a hat by Philip Treacy.
Warren said of the Queen: "Every race that takes place every day of the week, the Queen will certainly read the Racing Post every morning, look at the breeding of all the winners the day before, and see that these stallions that she uses will be potential horses for her own mares."
Despite not yet being in attendance, the Queen penned the introduction to the race card, where she praised the organisers for the event being able to go on behind closed doors in 2020.
She wrote: "Despite the challenges presented by the pandemic, I was most impressed by the efforts of many people who enabled last year's meeting to take place, helping to maintain the integrity of the British racing calendar.
"And after their absence in 2020, I am particularly pleased that some spectators will once again have the opportunity to visit the course for this unique and special occasion."
She added: "Breeders – as well as owners, trainers and jockeys – are at the heart of racing, and I was interested to learn those fortunate enough to breed a winner this year will again receive a permanent memento of their achievement."
The Queen wished everyone involved a "memorable and enjoyable week".
Royal Ascot began on Tuesday and takes place over five days.
Watch: The Royal Family's love of horses