At Birkhall, the 14-bedroom Jacobean hunting lodge where the King and Queen have been based for much of January, there is a mood of optimism at the start of a new year.

The King is continuing his cancer treatment but the prognosis is now encouraging enough to ensure that aides have begun planning his diary for 2026.

His beloved daughter-in-law, the Princess of Wales, is in remission from her cancer and there are hopes that, after a year in which the number of royal engagements carried out by the Windsors dropped to the lowest level – outside the pandemic years – since at least the 80s, the “Firm” will gradually return to a more normal 2025.The 76-year-old monarch, who has already undertaken a series of official engagements in London, Norfolk and Scotland in January, has a busy diary ahead. He will return to the international stage on 27 January when he joins world leaders at a sombre ceremony in Poland marking the 80th anniversary of the liberation of the Nazi death camp at Auschwitz.

But amid all the positivity about his and Kate’s health, there is a dark cloud looming over the skyline – the prospect of his younger son, Prince Harry, the Duke of Sussex, upsetting the apple cart with a series of court cases that risk embarrassing the monarchy.

Prince Harry, left, with mayor of Pasadena Victor Gordo, right, and a unidentified woman at a home that was destroyed during the LA wildfires (Photo: MediaNews Group/Pasadena Star-Ne)

In between criticising Facebook owner Meta for stopping fact-checking and helping friends displaced by the Los Angeles fires that have threatened to spread up the coast to his and Meghan’s $29.6m (£24.3m) home in Montecito, Harry, 40, is prepping for a long awaited blockbuster legal case in London, beginning next Tuesday.

Harry and the former Labour deputy leader Lord (Tom) Watson are suing News Group Newspapers (NGN), the publishers of The Sun, for alleged unlawful newsgathering involving use of private investigators or reporters “blagging” information via deception and, in the case of Watson, phone hacking.

Why should that worry the King? Well, Harry wants to expose what he believes were shabby backroom deals between the Palace and the Murdoch organisation. He has previously accused his family or their aides of trading private information about him in return for favourable treatment of others, including Queen Camilla.

King Charles on a visit in Scotland this month. Aides have begun planning his diary for 2026 (Photo: Jane Barlow/Pool via AP)
During the 10-week trial set to start next week, the Duke – who has sought access to emails between NGN executives and senior figures at the palace including the late Queen’s private secretaries – intends to argue that his father “acted to discourage and stymie” him from taking legal action against the Murdoch press.

It is the source of some tension between father and son, along with the prospect of a second case in April in which Harry will appeal against a High Court ruling dismissing his challenge to the Home Office over its refusal to automatically allow him and his family police protection when they come to Britain, and then a case against the publishers of the Daily Mail in January next year in which he accuses the newspaper of hacking his phone. Associated Newspapers, which owns the Daily Mail, has always denied involvement in unlawful practices.

Palace officials shy away from discussing the rift but royal insiders say it is unlikely that Harry, who – despite reports to the contrary – is not expected to receive police protection when he comes to Britain for the case against The Sun, will stay at a royal residence or spend much if any time with his father while he is here.

Sally Bedell Smith, a distinguished American royal biographer, said his son’s decision to sue the Government in the police protection case had put the King in an embarrassing position. There may also be trust issues in The Sun case after Harry’s earlier disclosure of family conversations. “There is always the suspicion that Charles will say something that could be used by Harry,” she said.

In their pursuit of The Sun, Harry and Watson are the last two holding out among more than 1,300 people – including stars such as Sir Elton John, Hugh Grant, Liz Hurley, Heather Mills, Spice Girl Mel C, comedian Catherine Tate, Les Dennis, footballer Jonathan Woodgate, and boxer Frank Bruno – who reached out-of-court settlements with the publishers in a scandal that has cost Rupert Murdoch’s British newspaper operation more than £1bn.

Hugh Grant, Catherine Tate and Sir Elton John have reached out of court settlements after pursuing The Sun newspaper
Harry, however, and the Labour peer have resisted attempts by NGN to settle also, insisting they want their day in court to expose what they say are the worst practices of the Murdoch press.

It is a costly decision. When Hugh Grant reached a settlement for “an enormous sum of money” with The Sun last year, he explained that he could have faced a legal bill of £10m even if he had won under the rules of civil litigation which specify that if the court awarded him even a penny less than the settlement offer, he would have to pay both sides’ legal fees.

Harry has publicly acknowledged he will now indeed have to pay Murdoch’s legal fees as well as his own and any damages won will be dwarfed by the legal bill “100 times over even if or when we win”, he told The New York Times DealBook summit last month.

After Grant’s disclosure there has been speculation that the Duke is facing a legal bill of between £10m and £15m but a source in the legal profession who has been following the case closely told The i Paper this week that a figure of £4m to £5 million was more likely.

“The goal is accountability. It’s really that simple,” Harry said last month. “I know why people have settled. They’ve settled because they’ve had to settle. So therefore one of the main reasons for seeing this through is accountability, because I am the last person that can actually achieve that, and also closure for these 1,300 people and families.”

Might Sir Elton and some of those other victims who were forced to settle be helping to back him financially? Nobody in his camp will say.

Harry is expected to have four days in the witness box later in the trial in mid to late February facing questioning about his specific claims that he was the victim of unlawful information gathering by representatives of The Sun from 1996 to 2011.

Prince Harry is expected to appear in thr witness box later in the trial (Photo: Kevin Mazur/Getty)

But before his appearance, the first two weeks of the trial will be devoted to “generic issues”, during which lawyers for the prince and the former politician hope to set the scene by drawing on evidence gathered in the past few years to paint a picture of unlawful newsgathering on an industrial scale in The Sun’s newsroom.

They will claim that it could not have happened without the knowledge of senior executives and, to the disappointment of Murdoch’s lieutenants, they have also been given time to explore the claim that thousands of emails were destroyed unlawfully on the orders of bosses at News International, the former company overseeing the papers, between 2010 and 2011.

Harry’s claim to be a victim of phone hacking, something The Sun has always insisted did not occur at the paper, was struck out at an earlier hearing but Watson is alleging he was hacked and is expected to produce the former Labour prime minister Gordon Brown as one of his witnesses.

Harry has cited 30 articles and 20 incidents between 1996 and 2011 in which he claims that 16 private investigators and 23 journalists invaded his privacy. Watson alleges unlawful information gathering and phone hacking from 2009 to 2011. NGN denies that any of its titles ever hacked Watson and will argue his claim is brought out of time.
Harry has publicly acknowledged he will have to pay Rupert Murdoch’s legal fees (Photo: Gilbert Carrasquillo/GC Images)

Some media commentators have speculated that it promises to be too damaging for Murdoch to allow it to go ahead, and that a deal is in the offing.

Perhaps tellingly, neither side would comment this week on mounting speculation that a settlement is being discussed but both insisted they were still preparing for trial. “NGN’s case will involve a range of relevant witnesses to defend the case, including current and former employees,” a spokeswoman for the publishers said, adding that Harry’s claim would be fully defended, including on the grounds that it is brought out of time.

Up until now, The Sun has refused to admit liability in any of the 1,300 cases it has settled, although its late sister paper the News of the World did in a number of earlier hacking complaints. Harry and Lord Watson would clearly want a public admission of liability and a grovelling apology.

But the Duke is on a bigger crusade to shame sections of the British media and seek what he sees as justice from his family and the Royal Household. It is likely he would also want a deal with the Government to restore his police protection, something unlikely to be in the power of either Murdoch or his father to fix.Many of the courtiers, the senior advisers to his father and the late Queen he fell out with and blamed for “Megxit”, have now left the household. The King has a new Lord Chamberlain, Baron Benyon, and a new Keeper of the Privy Purse, James Chalmers.

But his key adviser remains his principal private secretary, Sir Clive Alderton, nicknamed The Wasp in Harry’s memoir Spare and described as “lanky, charming, arrogant”. Last November, Princess Diana’s biographer Tina Brown claimed that Sir Clive was considering retiring. It has led to speculation that his departure could clear the way for a reconciliation between father and son.

However, Brown’s claim was news to Sir Clive, who has told colleagues he has no plans to leave the household. Besides, he and the other courtiers who incurred Harry’s wrath were only carrying out the wishes of the then Queen, Charles, and Prince William.