The Queen is under medical supervision at Balmoral after doctors became concerned for her health, Buckingham Palace has said.

All the Queen's children are either at, or are travelling to, her Scottish estate near Aberdeen.

"Following further evaluation this morning, the Queen's doctors are concerned for Her Majesty's health and have recommended she remain under medical supervision," a statement said.

The Queen is comfortable, it added.

Prince Charles has travelled there with his wife, the Duchess of Cornwall.

The Duke of York and the Count and Countess of Wessex are travelling to the Scottish estate, about 40 miles (64km) west of Aberdeen.

The Princess Royal, Princess Anne, was already in Scotland undertaking engagements.

The Duke of Cambridge is also on his way, with the Duchess of Cambridge remaining in Windsor with their children on their first full-day at school.

The Duke and Duchess of Sussex, who were due to attend a charity event in London, are travelling to Balmoral, their spokesperson said.

Barriers are being placed outside one of the entrances to the estate.

The announcement comes after the Queen, 96, pulled out of a virtual meeting of her Privy Council on Wednesday, with doctors advising her to rest.

There are clearly pressing concerns for the Queen's health - much more explicitly put than before and without any reference to this only being about difficulties with mobility.

There are also warnings against unfounded speculation, such as that she might have had a fall. And on Tuesday she was on her feet and photographed smiling as she appointed new Prime Minister Liz Truss.

But from the last-minute cancellation of what would only have been a virtual meeting of the Privy Council - of senior ministers - there is no mistaking the fragility of the Queen's health.