Her eldest son and heir Prince Charles and his wife Camilla have travelled to her Scottish home, Balmoral Castle, where she is staying, along with his eldest son Prince William, officials said. Her other children – Anne, Andrew and Edward – were also on their way to the castle.
A spokesperson said Prince Harry and his wife Meghan, in Britain for a number of events, would also travel to Scotland.
Such a family gathering, outside of holiday events such as Christmas or Easter or major public events, is extremely rare.
The queen, Britain’s longest-reigning sovereign and the world’s oldest monarch, has been suffering from what Buckingham Palace has called “episodic mobility problems” since the end of last year.
She pulled out of a virtual meeting with senior ministers on Wednesday, a day after appointing Liz Truss as British prime minister.
A spokesperson said: “Following further evaluation this morning, the Queen’s doctors are concerned for Her Majesty’s health and have recommended she remain under medical supervision. The Queen remains comfortable and at Balmoral.”
A statement from Buckingham Palace:https://t.co/2x2oD289nL
— The Royal Family (@RoyalFamily) September 8, 2022
A palace source played down speculation that the monarch had suffered a fall.
Ms Truss said “the whole country will be deeply concerned by the news from Buckingham Palace this lunchtime” adding “my thoughts – and the thoughts of people across our United Kingdom – are with Her Majesty The Queen and her family at this time”.
The queen looked bright but frail and used a walking stick during Tuesday’s historic audience with Ms Truss, which followed a visit from outgoing prime minister Boris Johnson as he tendered his resignation.
The whole country will be deeply concerned by the news from Buckingham Palace this lunchtime.
My thoughts – and the thoughts of people across our United Kingdom – are with Her Majesty The Queen and her family at this time.
— Liz Truss (@trussliz) September 8, 2022
Keir Starmer, the leader of Britain’s opposition Labour Party, said he was deeply concerned about the news.
“Along with the rest of the country, I am deeply worried by the news from Buckingham Palace this afternoon,” he said in a statement.
Queen to appoint new UK prime minister at Balmoral…
Scotland’s first minister Nicola Sturgeon said on Twitter: “All of us are feeling profoundly concerned at reports of Her Majesty’s health. My thoughts and wishes are with the Queen and all of the Royal Family at this time.”
DUP leader Jeffrey Donaldson said his “thoughts and prayers and that of the DUP are with Her Majesty and her family at this time”.
The UK’s national broadcaster, the BBC, interrupted its scheduled programming to switch to rolling news bulletins following the announcement that doctors were concerned for the queen’s health.
Elizabeth has been queen of Britain and more than a dozen other countries since 1952, and earlier this year celebrated her 70th year on the throne.