The Queen is under medical supervision at Balmoral as doctors are "concerned" for her health.

The monarch has stepped back from public duties in recent weeks, and did not return to Buckingham Palace to accept the resignation of Prime Minister Boris Johnson and appoint successor Liz Truss.

A statement said: "Following further evalaution 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."

The news broke during a parliamentary session, with Truss and leader of the opposition Keir Starmer both briefed.

Truss said the "whole country" would be "deeply concerned" by the news.

She added: "My thoughts - and the thoughts of people across our United Kingdom - are with Her Majesty The Queen and her family at this time."

The monarch's immediate family members have been informed, with the latest announcement escalating fears for the monarch’s health.

Prince Charles, Prince William and the Duchess of Cornwall have all travelled to Balmoral, Clarence House said.

The Queen had earlier pulled out of a virtual privy council meeting after being advised by doctors to rest.

Commons Speaker Sir Lindsay Hoyle told MPs: “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."