Crowds are gathering outside Buckingham Palace as doctors monitor the health of Her Majesty The Queen.

People have gathered outside in London as the Queen's children and grandchildren travel to be with her in Balmoral after doctors said they were "concerned" for her health.

Police have put up barriers outside for members of the public to stand behind as they show their support for the monarch.

Her Majesty has been under medical supervision since this morning after doctors became concerned about her health.

Prince Charles, Princess and Prince William are at The Queen's bedside, while Prince Harry and Meghan Markle are traveling to Balmoral Castle.

Crowds began gathering outside Buckingham Palace in The Queen's absence this afternoon as the British people across the country come to show their support.

Prince Edward and Prince Andrew will also join the rest of the Royal Family shortly.

The growing crowds outside are waiting for further news about The Queen's health after a statement was put out by Buckingham Palace this afternoon.

It read: "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."

Surrey Comet: Crowds outside Buckingham Palace in London this afternoonCrowds outside Buckingham Palace in London this afternoon (Image: Immy Share)

Evie Blades, who works nearby, told us: "It feels so tense here." 

A statement about the Queen's health is exceptionally rare and suggests the situation is very serious. 

Minutes before the statement, the new Prime Minister Liz Truss was handed a note in the Commons informing her of the development as she was revealing her plans to cap energy bills for the next two years.

She later 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.”

The royal family’s website appeared to crash following the news of the Queen’s health concerns.

An error message appeared on screen reading: “Gateway time-out”.

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.”