The Queen will spend the day resting after suffering symptoms of gastroenteritis, Buckingham Palace said.
She was due to attend a military celebration in Wales today during the city's St David's Day celebrations, but has been forced to cancel her planned engagements because of the sickness.
She will instead spend the weekend at Windsor, a palace spokeswoman said.
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Elsewhere it’s largely dry, sunny and increasingly humid across the bulk of England and Wales.