The King was seen briefly in public for the first time since he had to be admitted to hospital for observation after developing side effects from treatment for cancer.

King Charles was driven out of Clarence House just hours after it was confirmed doctors had admitted him to the London Clinic for checks.

His Majesty rolled down the window of his car and waved to a sizeable crowd waiting for him.

There were cheers for The King as he was driven away at the start of the two hour journey to his Gloucestershire home at Highgrove where it’s understood he will rest over the weekend.

Several engagements lined up in Birmingham on March 28 were postponed after King Charles developed side effects from his cancer treatment. The exact cause for concern hasn’t been revealed and it’s been reported to be usual among patients undergoing similar procedures.

The King also had to postpone meetings with ambassadors scheduled for March 27 when he developed a reaction to treatment and was admitted to hospital for observation.

Queen Camilla had continued with her own engagements that day and returned home to dine with The King that evening.

They had company the following morning when Princess Anne popped in to see her brother. It’s understood they were together just ahead of his departure for Highgrove.

Last week, The King told cancer patients that he met in Northern Ireland that his attitude to his illness was to ”keep buggering on”.

His Majesty has had a busy few weeks with a three day stay in Northern Ireland as well as a host of engagements of his own in London as well as a supporting role at events hosted by Queen Camilla and by Princess Anne.

The King and Queen are due in Italy for a State Visit in early April and it has been reported that their engagements in Rome and Ravenna might now be spread across three days instead of two after their planned trip to the Vatican had to be postponed as Pope Francis continues to recover following a five week hospital stay for double pneumonia.