The King has been forced to cancel a string of engagements after being admitted to hospital today over his ongoing cancer treatment.

The 76-year-old monarch is back at Clarence House tonight, doing his usual work, with insiders saying it’s just a minor setback on the path to recovery.

To ensure he continues on his positive path to recovery, he made the difficult decision to cancel several commitments in Birmingham tomorrow.

Sources insisted there was ‘no drama’ and described the ‘brief’ trip to hospital this evening as being ‘connected to [his] treatment programme’.

This serves as a stark reminder that despite revealing over a year ago that he was battling an unspecified type of cancer, the king is still receiving treatment while maintaining a busy schedule of public appearances.

A source added: ‘As many can vouch, such things are not unexpected with these kind of conditions.’

His Majesty has been able to undertake a full programme of public and State duties, and that position remains unaltered, sources stress.

But today’s side effects did necessitate a brief hospital visit and a few ‘adjustments’ to his immediate diary programme.

In a statement Buckingham Palace said: ‘Following scheduled and ongoing medical treatment for cancer this morning, The King experienced temporary side effects that required a short period of observation in hospital.

‘His Majesty’s afternoon engagements were therefore postponed.

‘His Majesty has now returned to Clarence House and as a precautionary measure, acting on medical advice, tomorrow’s diary programme will also be rescheduled.

‘His Majesty would like to send his apologies to all those who may be inconvenienced or disappointed as a result.’

The King has personally been keen to be as open as possible about his diagnosis, while retaining a sense of medical privacy and was keen to share the latest news in a ‘spirit of openness and transparency’.

No further details of the side effects have been given but they are understood to have been temporary and such issues are not uncommon with many medical treatments.

The King is at home in Clarence House this evening, where he is in ‘good form’, and is continuing to work on State papers and make calls from his study.

He was treated in the London Clinic that has cared for him previously and he travelled to and from the hospital by car in the usual way. The Queen did not join The King during his brief visit to hospital.

A spokesman said of the cancelled engagements: ‘His Majesty was due to receive Credentials from the Ambassadors of three different nations this afternoon. 

‘Tomorrow, he was due to undertake four public engagements in Birmingham and is greatly disappointed to be missing them on this occasion.

‘He very much hopes that they can rescheduled in due course and offers his deepest apologies to all those who had worked so hard to make the planned visit possible.’

Buckingham Palace have indicated there are unlikely to any further updates as it is ‘not a major development’ but will advise on any minor alterations to next week’s diary that may be required in due course.

It is understood the announcement was made so late in the day as the King required time to consult with his staff and medical team about whether tomorrow’s engagements should proceed.

As a precautionary measure, to protect His Majesty’s continued recovery, it was decided that on balance it would be wiser to postpone tomorrow’s engagements.

Charles has been carrying on with his duties despite facing a personally challenging 2024 in which both he and the Princess of Wales were diagnosed with cancer.

The King’s cancer diagnosis was announced in February and he has been receiving treatment for an undisclosed form of the disease as an outpatient. 

He cancelled all face-to-face public duties but returned in April and has since travelled to France for D-Day commemorations, hosted incoming state visits for the Emperor of Japan and the Emir of Qatar, and undertaken a hectic tour to Australia and Samoa with the Queen, despite still undergoing outpatient cancer treatment.

Buckingham Palace have never revealed what cancer the king has – aside to say it was not connected with the prostate surgery he underwent in January which result in doctors discovering the disease – nor details of his treatment. 

However the Mail has previously revealed that it was caught at a very early stage.

It is understood that his treatment is ongoing and the recovery path continues ‘in a very positive direction’.

No major changes to his programme are anticipated but a decision may yet be taken to lighten limited elements of the full planned programme to protect and prioritise His Majesty’s continued recovery, acting on the advice his medical team, and in preparation for the State Visit to Italy in just over a week’s time.

Queen Camilla has spoken of her personal frustration that her adored husband will not slow down. 

But sources say His Majesty’s diary programme is developed in ‘full consultation’ with his medical team at all stages to protect and prioritise his continued recovery.

They stress that the reaction of any patient to medical treatment can be unpredictable and it makes sense to make minor adjustments to plans as necessary.

They also believe undertaking public and State duties has been of great benefit to the King’s overall wellbeing and Charles is ‘deeply grateful’ for all the support, encouragement and kind words of the many thousands he has met while doing so.