Her Majesty was due to attend a military celebration in Wales during the country's St David's Day celebrations, but was forced to cancel her planned engagements.
Buckingham Palace declined to comment on her condition, but a spokeswoman earlier confirmed the Queen would spend the weekend at Windsor.
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It comes after a report found more than 450 patients had their lives shortened after being prescribed powerful painkillers.
“Shocking” revelations over deaths at a hospital lead most of the papers.
Amanda Spielman will tell the Festival of Education she also supports schools that take a tough stance on unruly pupils.