Prince Harry is not thought to have seen his father King Charles before the monarch jetted off for Italy, MailOnline can reveal today.

The Duke of Sussex arrived from Los Angeles on Sunday while his father spent the weekend at Highgrove, his private residence in Gloucestershire, resting before the upcoming State Visit to Italy this week.

His youngest son flew into London from California at the weekend ahead of his High Court showdown today.

At the Royal Courts of Justice, the Duke of Sussex is present to support his own appeal concerning the security arrangements for himself, Meghan Markle, Archie, and Lilibet while in the UK.

But despite being in the same country for some hours, the King and Harry are not believed to have spent any time together on Sunday.

Buckingham Palace declined to comment on the meeting or the King’s movements.

His Majesty traveled to Rome directly from RAF Brize Norton with Queen Camilla on Monday afternoon. This decision followed the revelation by Richard Eden of the Mail that Harry had chosen to miss the wedding of one of his close friends, despite receiving an invitation and being in the country.

Today, just as Harry walked purposefully into the Royal Courts of Justice for the 10am hearing, Charles and Camilla were afforded a ceremonial welcome including a flypast by Italian President Sergio Mattarella and his daughter, Laura Mattarella, at the Quirinale Palace on Tuesday.

A sombre Prince Harry has arrived at the High Court in London today 

The Duke of Sussex is at the Royal Courts of Justice for the start of his appeal against a High Court ruling on his legal claim against the Home Office

But MailOnline can reveal he did not see his father, pictured today in Rome with Queen Camilla, when they were briefly in the US at the same time on Sunday and Monday

Harry waved to the crowds outside amid the ongoing rows with the UK Government and also his family

The Duke of Sussex has decided to travel 5,000 miles to be at the High Court in London to support his own appeal against a ruling on the level of security he, Meghan Markle, Archie and Lilibet are afforded while in the country of his birth.

Wearing a suit, white shirt and tie, Harry arrived looking stern, clutching his mobile phone tightly. There was a brief smile and wave as he entered the historic building.

Harry’s long-term personal bodyguard Dave Langdown, 57, a former Metropolitan Police officer, entered the courtroom 20 minutes before the case was due to start. He scanned the room to ensure it was safe for the Prince’s evidently imminent arrival.

At 10.24am Prince Harry himself walked into court, clad in a charcoal grey suit. Offering a forced smile grimace to the media, he took a seat in the third row back from the judge, two rows behind his two King’s Counsel barristers, Shaheed Fatima and Jason Pobjoy.

Mr Langdown took a seat in the public gallery behind his boss.

Harry believes he is entitled to armed bodyguards, paid for by the British taxpayer, and is fighting a 2020 decision to reduce the level of security after he and Meghan Markle stepped back from life as working royals and emigrated to the United States.

He has expressed safety concerns about returning to the UK with his wife and children.

It came after landed in the UK just before King Charles III jetted off to Italy for a historic four-day state visit.

The King and his son are also believed to have differing views over Harry’s decision to pursue his legal fight with the Home Office, which has cost the British taxpayer £500,000 so far. 

Harry has been taking legal action in the UK over a decision made by the Executive Committee for the Protection of Royalty and Public Figures (Ravec) in February 2020 over the level of protection he should receive when in the country. 

The High Court previously heard that his ‘status’ had changed as a result of no longer being a ‘full-time working member of the Royal Family’.

But Harry has argued his children, Prince Archie and Princess Lilibet cannot ‘feel at home’ or ‘safe’ in the UK unless his police protection is fully restored. 

His legal fight comes as the Charity Commission announced it had launched an investigation into Sentebale, the charity he founded, amid a bitter boardroom rift between Harry and chairwoman Dr Sophie Chandauka.

She has accused Prince Harry of ‘harassment and bullying’ – a claim that is denied.

Prince Harry flew into the UK just hours before King Charles jetted off to Italy for a historic four-day state visit

There was a brief smile for the cameras when Harry arrived. There were shouts asking whether he had seen his father

King Charles III and Queen Camilla are received by the President of the Italian Republic, His Excellency Signor Sergio Mattarella and the President’s daughter, Signora Laura Mattarella at the Quirinale Palace f

Meanwhile in Rome, Italy’s President Sergio Mattarella (R) welcomes Britain’s King Charles III at the Quirinale Presidential Palace

King Charles III, Queen Camilla, President of the Italian Republic, His Excellency Signor Sergio Mattarella and the President’s daughter, Signora Laura Mattarella view a flypast by the Frecce Tricolori and Red Arrows at the Quirinale Palace

King Charles and Queen Camilla are in the Italian capital, Rome, pictured at at Villa Wolkonsky

King Charles III and Queen Camilla arriving at Giovan Battista Pastine International Airport

For his part Harry, who stood down as patron of the charity last week alongside co-founder Prince Seeiso in support of a group of trustees who have also quit, has accused Ms Chanduaka of telling ‘blatant lies’.

He said they ‘fully expected [the investigation] will unveil the truth that collectively forced us to resign’. 

Prince Harry added: ‘We remain hopeful this will allow for the charity to be put in the right hands immediately, for the sake of the communities we serve.’

His arrival in the UK capital comes as the King and Queen jetted into Rome, before visiting the city of Ravenna, as they use the ‘soft power’ diplomacy of the monarchy to strengthen Britain’s relationship with its ally.

A separate state visit to the Holy See, the government of the Roman Catholic Church, in the Vatican, has been cancelled, as Pope Francis is recuperating after leaving hospital following treatment for double pneumonia.

With a number of Vatican events removed from the itinerary in Rome, the remaining engagements in the Italian capital have been spread over two days, and extra elements added to some engagements.

At the weekend the Pope made a surprise appearance in St Peter’s Square, in the Vatican. 

He appeared with an oxygen tube under his nose and was using a wheelchair.

King Charles waves from a car as he and Queen Camilla depart the Rome Ciampino Airport at the beginning of their four-day state visit to Italy

The King and Queen pictured departing their flight ahead of their historic state visit to Italy

Ciao fella: It is not known if King Charles III and Prince Harry met between their flights

The Duke of Sussex is back in London for an appeal against a High Court ruling on whether he is entitled to armed bodyguards paid for by the taxpayer

The prince’s legal fight comes as the Charity Commission announced it had launched an investigation into Sentebale, the charity he founded, amid a bitter boardroom rift between Harry and chairwoman Dr Sophie Chandauka (pictured)

Dr Sophie Chandauka, pictured with Meghan and Harry at a polo event last year that sparked a row. A year on the trio have fallen out and the Duke of Sussex resigned from Sentebale

King Charles III and Queen Camilla at Clarence House in London on March 25

Charles will hold audiences with President Sergio Mattarella and Prime Minister Giorgia Meloni 

Charles will become the first British monarch to address both houses of Italy’s parliament – the chamber of deputies and the senate of the republic.

The King will also hold audiences with President Sergio Mattarella and Prime Minister Giorgia Meloni, and he and his wife will attend a black-tie state banquet at the Palazzo Quirinale, hosted by the president on the evening of their 20th wedding anniversary.

The UK and Italy’s defence co-operation will be marked by a joint flypast over Rome by the Italian air force’s aerobatic team, Frecce Tricolori, and the RAF’s Red Arrows.

In Ravenna, near Bologna, Charles and Camilla will mark the 80th anniversary of the province’s liberation from Nazi occupation by allied forces, on April 10 1945, during a town hall reception.

Charles and Camilla will attend a black-tie state banquet at the Palazzo Quirinale (pictured)

Pope Francis speaks to the faithful in St Peter’s Square at the Vatican yesterday

They will celebrate literary culture by visiting Dante’s tomb and the Queen will make a solo trip to the Byron museum.

Charles returned to official public duties after cancelling a string of engagements last month, when he experienced temporary side effects from cancer treatment on March 27.

Buckingham Palace announced that the King had ‘required a short period of observation in hospital’ earlier that day.

Planned engagements in Birmingham the following day, March 28, were cancelled to prioritise his recovery as a precautionary measure.

A source described it as a ‘most minor bump in a road that is very much heading in the right direction’.