On December 9, 1992, John Major stepped before the House of Commons and made a historic announcement that reverberated across the world. 

'It is announced from Buckingham Palace that, with regret, the Prince and Princess of Wales have decided to separate,' the then-Prime Minister confirmed Charles and Diana's relationship had run its course. 

Mr Major's statement marked the end of an incredibly tumultuous period for the Prince and Princess of Wales - dubbed 'The War of the Waleses' by the press due to their evident unhappiness in the years prior.

It was appropriate for Mr Major, who served as Prime Minister from 1990 until 1997,  to make the announcement since he had played the important role of an 'honest broker' between the feuding royals before. 

Mr Major was also a 'sympathetic listener to Diana at a time when she felt her most alone', royal expert Valentine Low noted in his book Power and the Palace. 

Citing Mr Major's private secretary Alex Allan, the author noted how the politician, now 82, was 'quite concerned' about the Princess and gave Diana a 'shoulder to cry on' during the breakdown of her marriage. 

Meanwhile, Diana's private secretary, Patrick Jephson, told Mr Low that the pair would meet regularly for tea, and Diana would humorously refer to Mr Major as 'the Hon. John'.

'I got the very clear message that she enjoyed those meetings. He was an important, sympathetic, helpful mentoring figure. And he did it when he ceased to be prime minister as well,' Mr Jephson is quoted as saying. 

Putting his diplomatic skillset to good use, Mr Major had several sessions with the respective royals in the build-up to their separation, while also updating the late Queen Elizabeth II on the state of their marriage during their 'weekly audiences'.

'Meanwhile, another royal aide shared how the politician had also "done his best" to ensure that Diana's young sons felt that the government cared about them,' Mr Low wrote. 

Princes William and Harry were 10 and eight respectively when news of their parents' separation was announced publicly.

However, Mr Major had another very important reason for wanting to mitigate the fallout from Diana and Charles's separation, according to Lord Butler of Brockwell. 

He told Mr Low that while the Prime Minister 'would have been naturally sympathetic' towards Diana,  he could also foresee the damaging implications the Wales' separation could have for the sovereign and sought implicitly to 'protect the monarchy as an institution'.

Certainly, there may also have been an innate feeling by the Royal Family that the empathetic and rational leader possessed the necessary capabilities to help resolve the crisis. 

During periods where things were said to have been 'really hairy' between Charles and Diana, Mr Jephson reportedly 'got the sense that Buckingham Palace had an "understandable wish" that Number 10 would sort things out'.

'Ironically, the role of the monarchy is to act as the continuity, the unchanging face of the state, but I remember thinking it was us who were in a mess,' he told Mr Low. 

'In Number 10, there was real power, real authority. They were sorting out the rest of the country, and wouldn't it be lovely if they could sort this out too?' 

On the day that Charles and Diana's separation was due to be announced in the House of Commons, Mr Major met them both separately and tried to reassure them.  

Once the proceedings for their separation officially began, he was said to have maintained a close relationship with the Princess as she sought to navigate public life on her own.

When Diana visited Nepal in 1993 with the overseas development minister, Baroness Chalker, Mr Jephson was instructed to keep a 'watching brief' on Diana on the Prime Minister's behalf.

Given the tour was a 'resounding success', Mr Major even considered the possibility of Diana taking on a role as a patron of an organisation related to childcare or something similar, though this never materialised. 

And when Diana's notorious interview with the BBC's Martin Bashir aired in 1995, Mr Major's fond feelings for the princess were said to have been made abundantly clear.

Shortly after the interview was viewed by more than 23 million people worldwide, Nicholas Soames, a close friend of Charles, went on the broadcaster's Newsnight programme and declared that he believed the princess was showing 'the advanced stages of paranoia'.

'Later, Major bumped into him in the division lobby of the Commons and told him firmly to "shut up",' Mr Low claimed.

In the years that followed the breakdown of Diana and Charles' marriage, Mr Major always spoke highly of his relationship with the princess and her role as a public figure.

Speaking to ITV News about the separation of the Prince and Princess of Wales in 1996, he described the 'whole affair' as 'very sad', adding that it had been 'a matter of discussion and negotiation'. 

'I think she is going to have a role. The Princess of Wales has a great deal of affection for her in this country as around the world. She is a member of the Royal Family, she will remain a member of the Royal Family. 

'She is going to have an important role in our public life as far ahead as we can see it,' he added.

Four months after he stepped down as Prime Minister, a forlorn Mr Major and his wife, Norma, attended Diana's funeral at London's Westminster Abbey on September 6, 1997.  

When Mr Low queried the politician about his relationship with the beloved 'People's Princess', Mr Major stressed that his role in managing the Waleses' separation was vital.

He said: 'The Royal Family are important to help our nation. The Prime Minister is the first minister for the Queen, and if she can help, I would hope that he or she would always do so, and never betray the trust that is placed in them.'