The Queen's doctors concerned for her health as she remains under medical supervision

A Palace 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."

Meanwhile, Clarence House has confirmed that the Prince of Wales and the Duchess of Cornwall have travelled to Balmoral, while Kensington Palace has confirmed that the Duke of Cambridge is also travelling at this time.

A Clarence House spokesman said: “Their Royal Highnesses the Prince of Wales and the Duchess of Cornwall have travelled to Balmoral.”

A Kensington palace spokesman added: “The Duke of Cambridge is travelling to Balmoral.”

Speaking of the news, Prime Minister Liz Truss said: “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.”

Meanwhile Commons Speaker Sir Lindsay Hoyle also shared his best wishes.

He told MPs at lunchtime: "I know I speak on behalf of the entire House when I say that we send our best wishes to Her Majesty the Queen and that she and the royal family are in our thoughts and prayers at this moment."

It comes after the monarch, 96, pulled out of a virtual Privy Council on Wednesday, a day after appointing Liz Truss as prime minister at her home in the Scottish Highlands.

The Queen has had ongoing mobility issues and looked bright but frail and used a walking stick during Tuesday’s historic audience with Truss.

“After a full day yesterday, Her Majesty has this afternoon accepted doctors’ advice to rest. This means that the privy council meeting that had been due to take place this evening will be rearranged," Buckingham Palace said.

Throughout her reign, the Queen has always had an audience at Buckingham Palace during the changeover of a Prime Minister.

However, this time she remained in Balmoral with both Liz Truss and Boris Johnson travelling to her on Tuesday.