The exchange, of only a few words, was seen as a breakthrough in the brothers’ relationship at the time.

But since then, Prince Harry and Prince William have failed to keep up the display of unity.

Following the death of their grandmother, they were seen putting their conflict behind them and acting in a civil way towards each other. 

Shortly after the Queen’s committal service in September 2022, an expert lip reader revealed what Harry said to William as they were taking their seats at the chapel at Windsor Castle.

William appeared to step aside for Harry and Meghan. As William stood at the entrance to the front pew, Harry asked him: ‘Shall we go through first?’

William nodded, before telling his wife Kate: ‘Let them go through first.’  

At the time MailOnline reported that the brothers ‘put aside their feud for a united front to remember the monarch and again showed that they could at least be on speaking terms’. 

Prince William and Prince Harry walk together after looking at floral tributes to the Queen outside Windsor Castle in September 2022

The Waleses and the Sussexes were last seen together in a united front at the Queen’s funeral

An expert lip reader revealed what Harry said to William as the brothers were taking their seats before the Queen’s committal service

But the occasion marked Meghan’s last time visiting the UK – with Harry returning sporadically on his own.

The rift between the Sussexes and the rest of the family has only grown as the couple publicly chastised the Firm.

In his tell-all memoir Spare, Harry describes how his position left him seemingly bubbling with resentment, writing: ‘I was the shadow, the support, the Plan B. I was brought into the world in case something happened to Willy.

‘I was summoned to provide back-up, distraction, diversion and if necessary, a spare part. Kidney, perhaps. Blood transfusion. Speck of bone marrow.’

Ingrid Seward, who has spent 40 years following the royal family, claimed that Harry’s emotional problems were caused by him allowing the ‘Spare’ label to ‘dominate his life – to the extent that he has now made a career out of it’.

She said: ‘He chooses to be the victim and wreak vengeance on the slights he thought he had suffered; on his family, on the Press and through the courts.’

In 2019 rumours started circling that Harry and William had fallen out, which Harry addressed in the documentary Harry & Meghan: An African Journey.

He said: ‘Part of this role and part of this job, and this family, being under the pressure that it’s under, inevitably, you know, stuff happens.’

 The brothers pictured at the Queen’s Golden Jubilee at St Paul’s Cathedral in 2002

In 2019 rumours started circling that Harry and William had fallen out. The princes are pictured at Highgrove in 1999 

William and Harry sitting together at the steps of Highgrove, wearing military uniforms, in July 1986

He continued: ‘But look, we’re brothers, we’ll always be brothers.

‘And we’re certainly on different paths at the moment, but I’ll always be there for him, as I know he’ll always be there for me.’ 

In a clip which resurfaced a few years ago, a 21-year-old Harry said of William: ‘He is the one person on this earth who, I can actually really, you know, we can talk about anything and we understand each other and give each other support and everything’s fine.’ 

The pair are believed to have formed a very close bond, united in adversity after the death of their mother Princess Diana in 1997, when Harry was just 12 and William was 15. 

Elsewhere in the interview, Harry added: ‘Every year we get closer. We’ve even resorted to hugging each other now after not seeing each other for long periods of time.

‘And yes, he does ring me when I’m away, and vice versa.’

He added that as the brothers have got older, he has began to give William advice.

‘Both privately and publicly we talk to each other about everything. If he has problems that he wants to talk about, then he comes to me. And apparently I give him quite good advice.’

William and Harry share a joke with Prince Charles during a photocall on the ski slopes in Klosters, Switzerland, in 2007

The brothers are believed to have formed a very close bond after the death of their mother Princess Diana in 1997. They are pictured in 1995

Harry and William speaking to Meghan in 2018 on the Buckingham Palace balcony 

But tensions only grew when the Sussexes decided to give up their royal duties and move to the US.

In 2020 Harry went to Sandringham, the royal estate in Norfolk, to discuss his and Meghan’s royal roles. 

Harry claimed in his Netflix docuseries Harry & Meghan that William screamed and shouted at him during the summit.

The Duke and his wife Meghan, the Duchess of Sussex, reportedly believed that establishing a happy life of their own would help thaw relations with the Royal Family.

The couple saw the removal of their police protection as a way of trying to strong-arm them into returning to the UK – since they felt that without security, visiting Britain would paint a target on their back.

In Spare, Harry went as far to call William his ‘archnemesis’ and said the pair have always ‘competed’.

According to royal historian Robert Lacey, Harry’s unhappiness with his role as the ‘spare’ only continued to grow stronger over the years, particularly as they grew older and it became increasingly obvious that William was being primed to take over the throne, while the younger sibling was given less attention and status. 

When Harry released Spare in January 2023, it quickly became apparent to royal fans that his malicious rivalry with William seemed to have always been there.

Harry’s position as the ‘Spare’ to his brother William dominated his life, according to one royal expert

Harry and William seem worlds apart at the unveiling of a statue of Diana at The Sunken Garden in Kensington Palace in 2021

Kate, William, Harry and Meghan greet well-wishers outside Windsor Castle in 2022

The brothers were last together in public at their grandmother’s funeral in September 2022.

They have been reunited a handful of times since the Sussexes’ move stateside and have attended some of the same events. 

Most recently, they both attended the funeral of their uncle, Robert Fellowes, last August, but it was reported that no one saw them speak.

Grant Harrold, who worked at King Charles’s personal home Highgrove between 2004 and 2011, spoke of a rekindling of the brothers’ relationship as part of a new documentary for 60 Minutes Australia.

He said the boys were a ‘team’ in childhood and always played ‘practical jokes’ on each other.

Mr Harrold believes that the rift between the future King and the ‘spare’ will not last forever.

William and Harry walk together to meet members of the public at Windsor Castle on September 10, 2022 

Prince Harry and the Duke of Sussex are seen speaking to a gardener as they unveil a statue of their mother in 2021

But royal author Tom Bower has said he felt that a reconciliation between Harry and his family was ‘totally unrealistic’.

He said: ‘There is zero chance of reconciliation because there is irreconcilable anger on the part of William and Kate.’ 

Time may be the greatest healer for the brothers, but it is unlikely they will entirely repair their childhood bond.

But, whenever the two princes are seen together, there is no doubt their every word and gesture will remain under the closest scrutiny.