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

It was added that the 96-year-old monarch "remains comfortable" at Balmoral Palace in Scotland

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.”

Prince Charles and Camilla have travelled to the Scottish residence to be with The Queen, Clarence House confirmed. 

The Duke and Duchess of Rothesay were staying at Birkhall and made their way to be by the Queen's side on Thursday. 

Prince William,  the Duke of York and the Earl and Countess of Wessex travelled to Balmoral this afternoon with a Royal Air Force aircraft landing in Aberdeen shortly before 4pm. 

HeraldScotland: The Duke of Cambridge drives a car carrying the Duke of York, and the Earl and Countess of Wessex into Balmoral in ScotlandThe Duke of Cambridge drives a car carrying the Duke of York, and the Earl and Countess of Wessex into Balmoral in Scotland

The Queen appeared well, but frail, in the most recent footage released by the Royal household. 

Ahead of the announcement, party leaders within the House of Commons passed a note before leaving the chamber temporarily. 

Commons Speaker Sir Lindsay Hoyle, new Prime Minister Liz Truss and Labour leader Keir Starmer left the chamber during PMQs. 

Upon his return, the speaker said: "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.”

Prime Minister Liz 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”.

There are no plans for the Prime Minister to travel to Scotland on Thursday or Friday, Downing Street said.

The Prime Minister’s official spokesman also said he could not give any updates on the Queen’s health or whether Liz Truss has been in touch with the Palace.

“The Prime Minister is working from Downing Street this afternoon in a series of meetings,” he said.

“As is standard, I wouldn’t get into any contact certainly between the Prime Minister and the Palace.”

The statement regarding her health comes after Queen Elizabeth pulled out of a virtual Privy Council on Wednesday. 

HeraldScotland: PAPA

The most recent image of the Queen

At Holyrood, Scottish Tory leader Douglas Ross approached the clerk sitting beside Presiding Officer Alison Johnstone to discuss the developments, as the faces of MSPs and ministers across the chamber registered shock and concern.

At the end of FMQs, Ms Johnstone told the parliament: “I will say at this point colleagues that I am aware that a statement has been made at Westminster on the health of Her Majesty the Queen. I will of course monitor developments and keep members updated over the course of the day.

“But my, and I’m sure the thoughts of all in Parliament, are with Her Majesty at the time.”

Scotland's First Minister Nicola Sturgeon said the news has left everyone "profoundly concerned". 

In a statement on Twitter she said: "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."

The Archbishop of Canterbury has said the “prayers of the nation” are with the Queen.

“My prayers, and the prayers of people across the (Church of England) and the nation, are with Her Majesty The Queen today,” Justin Welby tweeted.

“May God’s presence strengthen and comfort Her Majesty, her family, and those who are caring for her at Balmoral.”

BBC One has suspended all regular programming until 6pm following the news regarding the monarch's health. 

The broadcaster has been reporting on the news since 1pm but has now confirmed it will be the sole aspect of their coverage until later today. 

The monarch has been enduring mobility issues which has forced her to miss a number of royal events this year.

HeraldScotland: PAPA

Balmoral Castle 

Earlier this week, she appointed Liz Truss the UK's next Prime Minister from the Scottish estate - making her the first leader to be officially confirmed in Scotland.

She missed the Braemar Gathering highland games last weekend, which she usually attends each year.

During her Platinum Jubilee celebrations, the Queen only travelled to Buckingham Palace twice, first for her Trooping the Colour balcony appearance and then for a finale after the pageant.