Queen Elizabeth spent a night in hospital for first time in years

FILE PHOTO: Britain's Queen Elizabeth attends the opening ceremony of the sixth session of the Senedd in Cardiff, Britain October 14, 2021. Jacob King/Pool via REUTERS

LONDON (Reuters) -Britain's 95-year-old Queen Elizabeth spent a night in hospital for the first time in years for what Buckingham Palace termed 'preliminary investigations' but returned to Windsor Castle on Thursday where she was in good spirits.

The world's oldest and longest-reigning monarch cancelled an official trip to Northern Ireland on Wednesday. The palace said the queen had been told to rest by her medical staff, and that her ailment was not related to COVID-19.