Royal news – latest: King Charles observed in hospital following side effects of cancer treatment

The King has had a busy run of engagements this month, including a reception for media on Wednesday evening after a visit to a soil exhibition in the day, and is due to make a historic state visit to Italy in 10 days’ time.

It is understood the overseas tour with the Queen from April 7-10, which will see Charles become the first British sovereign to address both houses of the Italian parliament, is expected to go ahead as planned.

Last week, the King made a whirlwind three-day visit to Northern Ireland with Camilla, and earlier in March hosted high-profile audiences with key political figures including Ukrainian president Volodymyr Zelensky, outgoing Canadian prime minister Justin Trudeau and new Canadian PM Mark Carney.

Charles, who is known for being a workaholic, is said to have thrived on carrying out public and state duties in recent months, seeing them as being of great benefit to his overall wellbeing.

His long-haul visit to Australia and Samoa last autumn was described at the time as the “perfect tonic” for the monarch.

Since his diagnosis last year, the King’s diary of engagements is understood to have been developed in full consultation with his medical team at all stages to protect and prioritise his recovery.

Buckingham Palace said in a statement: “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 prime minister “wishes His Majesty the King all the very best”, a spokeswoman for Sir Keir Starmer said after the news was announced late on Thursday evening.

The King “required a short period of observation in hospital” after experiencing side effects from his cancer treatment, Buckingham Palace has said.

Charles has cancelled an away day to Birmingham on Friday to prioritise his recovery as a precautionary measure and is now back at Clarence House.

The King, 76, was said to be on good form at his London home where he is working on state papers and making calls from his study.