The Queen’s decision to cancel her attendance at COP26 is a big blow for the Prime Minister and the organisers of next week’s big UN Climate Change summit in Glasgow.
At a time when Boris Johnson admits success will be “touch and go”, the presence of the monarch at an event hosted by the UK is always a big draw.
The Queen’s appearance at the world leaders’ reception on Monday 1 November might even have been a reason for some leaders attending in person.
Others think that the respect she commands on the world stage might have encouraged some countries to sign up to the dramatic cuts in carbon emissions.
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Royal sources say the Queen hopes no one will use her withdrawal as a reason “to not attend”. She will also contribute in the best way she now can – via video link.
She wants COP26 to be a success and, we are told, she wants “to see meaningful actions”.
But the work of royal diplomacy, in whatever form you see it, will now fall to Prince Charles who will be the most senior member of the Royal Family present.
The Queen’s health has clearly dictated the decision and follows her doctor’s orders last week to rest after the tests she underwent overnight in hospital.
ITV News Political Reporter Shehab Khan on whether the Queen's cancellation will impact the success of COP26
This is a monarch who is not used to letting people down when it comes to attending important events in her diary.
She did manage to hold a some virtual audiences on Tuesday with two incoming ambassadors, which she did remotely from Windsor Castle.
And Buckingham Palace sources hint that she might undertake some similar light duties this week, including a phone call on Tuesday night with the Chancellor, Rishi Sunak, ahead of the Budget.
But it does now seem that after a busy October schedule, which many acknowledge was a lot for a 95-year old woman, her most senior staff are now putting her health before duty.