Prince Harry was in London Wednesday to mark the 10th anniversary of his Invictus Games for wounded military veterans, but no meeting was scheduled with his estranged father King Charles III.

As with all his trips to the UK since he moved to the United States in 2020, his three-day visit to the British capital has sparked a fresh round of speculation about a reconciliation with his family.

A possible end to four years of rancour and score-settling was seen as on the cards in February, when Harry jetted in from California to briefly see his father after it was announced that he had cancer.

But the palace doors look firmly shut to him this time round.

A spokesman for the Duke of Sussex, as Harry is also known, said on Wednesday that a meeting this week "will not be possible due His Majesty's full programme".

"The duke of course is understanding of his father's diary of commitments and various other priorities and hopes to see him soon," he added.

The king's "diary of commitments" has been less full than usual in recent months, as Charles, 75, receives chemotherapy for cancer.

But it is filling up again after doctors said they were "very encouraged" by the progress of his treatment, allowing him to ease back into official public engagements.

On Tuesday, the king was pictured meeting Fiji's Prime Minister Sitiveni Rabuka at Buckingham Palace, as Harry attended a discussion on the Invictus Games in London's financial district.

On Wednesday, the British head of state is expected to attend the first garden party of the year at Buckingham Palace and hold his weekly private audience with Prime Minister Rishi Sunak.

Commentators pointed out that Buckingham Palace is just under three miles (five kilometres) from the majestic dome of St Paul's, where Charles married Harry's mother, Princess Diana, in 1981.

As such, they interpreted the lack of meeting -- even for a short time -- as a snub, compounded by an announcement that Charles will appoint his elder son and heir Prince William as colonel-in-chief of Harry's old regiment.

- 'Regal middle finger' -

Former army captain Harry served as a helicopter pilot with the Army Air Corps in Afghanistan, where he later described eliminating targets as like removing "chess pieces" from a board.

No meeting with William is planned either. He is due on a visit to Cornwall in southwest England, and the Isles of Scilly on Thursday and Friday.

William's wife Catherine is also undergoing cancer treatment and has not made any public appearance since December last year.

The brothers, once close, are reportedly no longer on speaking terms due to Harry's criticisms of royal life in a succession of high-profile interviews, TV documentaries and his autobiography.

After Harry's three-day visit he is due to join Meghan on a trip to Nigeria.

Harry, 39, was characterised by the British media as a "party prince", who had none of the responsibilities of William, 41, who will become king after Charles.

But since marrying Meghan, an American former television actress, and quitting royal life, he has faced a sustained backlash in the UK, led by the tabloid press.

Former Daily Mirror editor and CNN host Piers Morgan, one of the most vocal critics of the couple, said Charles had given "a big regal middle finger to his treacherous younger son".

"It's clear from his 'scheduling issue' that Charles would rather impale himself on a rusty sword than meet up with someone who has wrought such vengeful misery on the Royal Family for so many years now," he wrote in The Sun.