The King won't be replaced following cancer diagnosis - but it is major setback

'It is a major setback': ITV News' Royal Editor Chris Ship reacts to King's cancer diagnosis

The King is not going to be replaced - at least not officially - but this cancer diagnosis was a hammer blow to his reign, so soon after he became Monarch.

Charles III has not just shared one health scare, but two.

The benign prostate operation, for which he spent three nights in hospital, is a condition men of the King's age, 75, have all the time.

But a diagnosis of cancer is of a different order.

Buckingham Palace will not tell us, yet, what cancer he has. The King will share this when his treatment is fully underway.

It is entirely possible his cancer has been caught early but we may also be looking at a scenario where this is not an early identification but something more developed - and therefore, more serious.

We should also consider why Prince Harry, after everything he has said about his family and the institution of monarchy in his book and his Netflix series, is heading to the UK as soon as he can to see his father.

Meghan is not travelling and will stay with the King's grandchildren, Archie and Lilibet, in California.

But it would appear this is the kind of diagnosis which is bringing a family together, when, for years, they've been so very far apart.

He is now being treated as an outpatient, which is why King Charles and Queen Camilla were relocated to London so his treatment can begin.

We are told there will be no need to install Counsellors of State - who are other senior members of the Royal Family who can stand in for a Monarch when he or she is incapacitated.

The King has been diagnosed with a form of cancer and has begun a schedule of regular treatments. Credit: PA

King Charles will still attend to his red boxes - the official papers sent to him by the government and there is certainly no prospect of a Regency - the like of which we haven't had for more than 200 years.

But it will mean this Monarch, a little like his mother before him, will have to withdraw from public duties to focus on his health.

That will put a greater burden on Queen Camilla, who will, more than ever, be living up to her title as Queen Consort in supporting the King.

It also puts a greater workload on the heir to the throne, Prince William.

We must consider the pressure he will be feeling given his wife spent nearly two weeks in hospital after serious abdominal surgery and the likelihood he will now have to pick up more public engagements on behalf of his father.

We await further news from Buckingham Palace, and many medics have commended the King for being so open about his two recent health conditions, but it is also a moment of huge uncertainty for the institution of which King Charles has so recently assumed control.

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