Queen Elizabeth spent Wednesday night in hospital for “preliminary investigations”, Buckingham Palace has confirmed.
The British monarch, who was ordered to rest by doctors and advised to miss a trip to Northern Ireland, returned to Windsor Castle at lunchtime on Thursday.
A church service marking the centenary of the partition of Ireland and the formation of Northern Ireland went ahead in Armagh on Thursday without the heads of state of either Ireland or Britain.
There was controversy last month over the decision by President Michael D Higgins to decline an invitation to the event organised by the leaders of Ireland’s five main churches. He said the title of the event was politicised and it would not be appropriate for him to attend.
Referring to the queen’s health, a Buckingham Palace spokesman said on Thursday: “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 overnight stay was said to be for practical reasons.
The Queen’s medical team are understood to have been taking a cautious approach.
The 95-year-old was said to be disappointed not to be able to travel to Northern Ireland on Wednesday, and reluctantly heeded the advice of her royal physicians.
She has had a busy schedule since returning from Balmoral at the start of October, and hosted a major Global Investment summit at Windsor Castle on Tuesday evening.
On Wednesday she cancelled her two-day trip to the North, citing advice from doctors.
“The queen has reluctantly accepted medical advice to rest for the next few days,” a Buckingham Palace spokesman said on Wednesday.
An official ceremony elevating the village of Hillsborough, Co Down to royal status went ahead in her absence.
In a statement, the organisers of the service, the Church Leaders’ Group, expressed sorrow that the queen could not attend.