Britain's 95-year-old Queen Elizabeth spent a night in hospital for preliminary investigations but returned to Windsor Castle on Thursday and was in good spirits, Buckingham Palace said.
The monarch cancelled an official trip to Northern Ireland on Wednesday with the palace saying she had been told to rest by her medical staff.
“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.
A royal source said the queen had stayed in hospital for practical reasons and that her medical team had taken a cautious approach.
She had returned to her desk for work on Thursday afternoon and was undertaking some light duties, the source said.