The Queen spent Wednesday night in hospital for preliminary medical checks and is now back at Windsor Castle "in good spirits", Buckingham Palace said.

The 95-year-old monarch returned from hospital at lunchtime on Thursday, the palace said.

The Queen was said to be "disappointed" after cancelling a visit to Northern Ireland on Wednesday.

She was given medical advice to rest for a few days, after a busy schedule of public engagements.

In a statement on Thursday night, Buckingham Palace said: "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."

She was pictured hosting a Global Investment Summit at Windsor Castle on Tuesday evening alongside Prime Minister Boris Johnson.