The Duchess of Cornwall, the Duchess and Duchess of Cambridge, the Earl and Countess of Wessex, and the Princess Royal continued to attend as planned.
Royal expert Jonny Dymond said the queen’s absence was a “blow” as many had hoped to see her.
He said: “This is a blow. A blow to those gathered here in Whitehall on the gray morning of November, a blow to those who hoped to see the Queen after a two-week break, and no doubt a blow to the Queen herself – on Memorial Sunday, she who devoted her life to service shows respect.
“It’s, as one palace official said, ‘an incredibly unfortunate timing.’