Queen Elizabeth II has spent a night in hospital for the first time in years for what royal officials termed “preliminary investigations” but was in good spirits and back at work at her Windsor Castle home on Thursday.
The world’s oldest and longest-reigning monarch cancelled an official trip to Northern Ireland on Wednesday.
The palace said the Queen, 95, had been told to rest by her medical staff, and that her ailment was not related to COVID-19.
“Following medical advice to rest for a few days, the Queen attended hospital on Wednesday afternoon for some preliminary investigations, returning to Windsor Castle at lunchtime today, and remains in good spirits,” the palace said in a statement on Thursday.
A royal source said the British monarch had stayed at the King Edward VII hospital in central London for practical reasons and that her medical team had taken a cautious approach.
She returned to her desk for work on Thursday afternoon and was undertaking some light duties, the source said.
The monarch had spent Tuesday night hosting a drinks reception at Windsor for billionaire business leaders such as Bill Gates after Prime Minister Boris Johnson convened a green investment conference ahead of the COP26 climate summit.
She had appeared in good health then, smiling happily as she met the guests.
Earlier this month, she was seen using a walking stick for support in public for the first time, apart from after her knee operation.
Her next major engagement is at the end of the month when she welcomes world leaders at the opening of the United Nations climate change summit in Glasgow.