ITV News Correspondent Royal Editor Chris Ship has the latest after the Queen's hospital stay
The 95-year-old Head of State went to hospital for “preliminary investigations” on Wednesday night but returned to Windsor on Thursday, said a Palace spokesperson.
It is said the overnight stay was for practical reasons and the Queen was back at her desk on Thursday afternoon undertaking light duties.
Her admittance is not believed to have been related to Covid-19.
A Buckingham Palace spokesperson 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."
It is thought the Palace had not planned to release the Queen's overnight hospital stay to the press were it not for a newspaper story due to be published on Friday morning.
Boris Johnson has passed on his best wishes to the Queen as she continues to rest following her overnight stay in hospital, Downing Street has said.
A No 10 spokesman said: “The Prime Minister’s best wishes have been passed on to Her Majesty.”
The spokesman declined to say whether Mr Johnson had had his weekly audience with the monarch.
The Queen had been due to spend two days in Northern Ireland this week but was forced to cancel last minute after being told by her doctors - known as the Medical Household - to rest following her attendance at a number of engagements.
Just days before, Her Majesty was seen walking with the aid of a stick at a Westminster Abbey service for the Royal British Legion.
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Buckingham Palace said at the time that there was no particular reason for the stick other than that she was using it for “comfort”.
She used it again when visiting the Welsh Parliament a few days later.
The last time the Queen was pictured using a stick was in 2003 - but this was after surgery to remove torn cartilage from her right knee.
When asked whether the Queen had attended too many engagements in October following the cancellation of the Northern Ireland trip, Palace aides said she had not appeared at any more than she had in June, for example.