Getty ImagesKing Charles III has cancelled his public engagements for Friday after experiencing temporary side effects during ongoing cancer treatment, Buckingham Palace says.
The side effects required a short period of observation in hospital, it added. The King has now returned to Clarence House, where he is continuing to work on state papers and make calls from his study.
Charles, 76, had planned to travel to Birmingham for a busy schedule of engagements on Friday, which included a tour of the city's Royal Ballet.
The palace first announced the King's cancer diagnosis in February 2024.
A Buckingham Palace spokesperson said meetings with three ambassadors on Thursday were also affected.
"Tomorrow, he was due to undertake four public engagements in Birmingham and is greatly disappointed to be missing them on this occasion," the palace's statement added.
"He very much hopes that they can be rescheduled in due course and offers his deepest apologies to all those who had worked so hard to make the planned visit possible."
A palace source described it as a "most minor bump in a road that is very much heading in the right direction".
The palace did not provide further information over what his side effects were.
As well as a visit to the Birmingham Royal Ballet, the King was due to tour the Oratory of St Philip Neri, open the new Midland Metropolitan University Hospital and tour the Sikh place of worship, the Guru Nanak Nishkam Sewak Jatha Gurdwara.
The palace has never disclosed what type of cancer the King has. He returned to public duties last April after a period of treatment and recuperation.
