The Prince of Wales has retuned to royal duties after his wife’s abdominal operation and is now the monarchy’s most prominent public figure following the King’s cancer diagnosis.

For some time William, as heir to the throne, will be the leading member of the royal family at official events across the country as his father receives treatment.

William began his working day by hosting an investiture ceremony at Windsor Castle, awarding honours like CBEs, OBEs and MBEs to recipients, and during Wednesday evening he will attend a gala fundraising dinner for London’s Air Ambulance Charity.

His brother, the Duke of Sussex, appeared to be heading back to the US as he was pictured at Heathrow Airport on Wednesday afternoon, just 24 hours after arriving in the UK to be with his father following the news of his diagnosis.

Harry and Charles’ first face-to-face encounter for many months appeared to last for as little as 45 minutes on Tuesday, and it was understood the Prince of Wales had no plans to meet with his brother.

On Wednesday, William received “best wishes” for the King from former England striker Ellen White, when he made the ex-Lioness an MBE for services to football, and told another recipient that he appreciated his words of support for both Kate and Charles.

The King’s cancer treatment as an outpatient started earlier this week, and he returned, with the Queen, to his Sandringham home in Norfolk on Tuesday after seeing Harry.

Charles has postponed all public-facing duties, but is continuing with behind-the-scenes work on his red boxes of state papers.

Downing Street took the unusual step of confirming details about Prime Minister Rishi Sunak’sweekly audience with the King, following an agreement with Buckingham Palace, and said it would be held later over the phone.

William may step in to represent his father at an event, but no engagements are scheduled at the moment and the royal palaces will make arrangements if the need arises.

Kate left hospital last Monday and returned to Adelaide Cottage in Windsor to be reunited with her three children after undergoing planned abdominal surgery on January 16 at the London Clinic.

William, 41, took time off work to support his family and planned to return once Kate’s care and recovery had settled, but the 42-year-old future queen is not expected to return to official duties until after Easter.

The prince last carried out a major royal event more than three weeks ago, when he travelled to Leeds to make former Leeds Rhinos team-mates Rob Burrow and Kevin Sinfield each a CBE for raising funds and awareness for motor neurone disease.

At the same private hospital that cared for Kate, the King received treatment for an enlarged prostate and was discharged the same day as his daughter-in-law, but on Monday, Buckingham Palace announced Charles had been diagnosed with a “form of cancer”.

White chatted briefly to William, president of the Football Association, during the investiture ceremony and said afterwards it must be a “difficult” time for the royal family.

The former striker, who was part of England’s Euro 2022 winning team, said to the PA news agency about the conversation: “I sent my best wishes to the King.

“I just think, you know, it must be a difficult time for the family.”

David Shreeve, who co-founded the Conservation Foundation charity with TV botanist David Bellamy, was made an MBE and said after the ceremony: “I did say to him at the end that I wished both his wife and his dad good luck.

“He said he appreciated it,” added Mr Shreeve, who was recognised for services to the environment.