The Spanish monarchy is in meltdown. In fact, its troubles make even our own House of Windsor look like a perfectly happy family.

For the 800-year-old House of Bourbon, which has ruled Spain since the 18th Century, is embroiled in allegations of infidelity and deception that implicate none other than Queen Letizia herself.

One of the Queen’s great strengths, according to Spanish media, was that she had been scandal-free. But after 19 years married to King Felipe VI, her image is under fire.

She stands accused of committing adultery, during the early years of her royal marriage, with a man called Jaime del Burgo. Astonishingly, after the Queen ended the affair, del Burgo would go on to marry her sister, Telma Ortiz, becoming his ex-lover’s brother-in-law.

COPENHAGEN, DENMARK: Queen Letizia of Spain attends a dinner at Christiansborg Palace

Spanish Crown Prince Felipe de Bourbon and his bride Letizia look at each other as the Royal couple appears on the balcony of Royal Palace May 22, 2004

Telma Ortiz and her husband Jaime Del Burgo pictured in 2012 prior to their wedding

The businessman, who made his fortune as an investor and financial adviser, claimed in a series of since-deleted social media posts last weekend that while the pair had dated before she met Crown Prince Felipe in 2004, they rekindled their relationship in 2010 for a further 18 months.

Felipe, 55, and Letizia, 51, now find themselves in the eye of a PR storm that threatens to wreck their reign, humiliate their two teenage daughters and perhaps even destroy the Spanish monarchy itself.

Chaos has long followed the Spanish royal family. Between 1931-75, Spain had no recognised monarch as the nation flirted with abolition, fought a civil war and laboured under General Franco’s dictatorship.

So when the rightful heir, King Juan Carlos I, ascended the throne in 1975, the Spanish people hoped for many years of stability.

However, in 2014, he was forced to abdicate amid a string of financial controversies, allegations of corruption and revelations about extra-marital affairs.

Juan Carlos has spent the past three years in self-imposed exile in the United Arab Emirates, his reputation in tatters and with public faith in the monarchy at its lowest point since his coronation.

The latest allegations against Queen Letizia first surfaced last month when journalist Jaime Penafiel published a book titled: Letizia & I: What Secrets is Queen Letizia hiding? Its claims have since been backed up in a series of tweets by Penafiel’s main source, Jaime del Burgo. 

King Felipe of Spain, Princess Sofia of Spain, Queen Letizia of Spain and Princess Leonor of Spain visit Los Jardines de la Alfabia gardens in Bunyola

MADRID, SPAIN: King Felipe VI of Spain and Queen Letizia of Spain receive Israeli President Reuven Rivlin and wife Nechama Rivlin for a Gala Dinner

The wild claims include that Letizia considered divorcing King Felipe to be with del Burgo, that they explored buying a house together close to the royal Zarzuela Palace in Madrid and that they even discussed having a child via surrogacy. 

Del Burgo corroborated his shocking claims by posting a selfie, apparently dating to the mid-2000s, of Letizia draped in a black pashmina and visibly pregnant with the King’s daughter. 

He claims the image was taken in a bathroom mirror during their affair and that she sent it to him along with the message: ‘Love. I am wearing your pashmina. It is like feeling you by my side. It looks after me. Protects me. I am counting the hours until we see each other again. Love you.’

Del Burgo claims the pair were in a ‘loving relationship’ from 2002 to 2004.

 According to Penafiel’s book, Letizia would rendezvous with del Burgo at the Santo Mauro hotel in Madrid, where David Beckham stayed while playing football for Real Madrid.

They also met at the Juan Carlos I hotel in Barcelona, named after Felipe’s father, as well as at the famed Danieli hotel in Venice.

Their relationship became so serious that del Burgo planned to ask for her hand in marriage over a romantic dinner in the garden of the Ritz Hotel in Madrid in 2004.

Businessman Jaime Del Burgo shared this unseen selfie of Queen Letizia with his X followers. He claimed that the royal was wearing his pashmina and said it ‘took care of her’

But moments before he went down on one knee, Letizia revealed she had met someone else — a young man for whom she would have to give up her promising career as a TV journalist.

She didn’t reveal the identity of her mystery lover, only that he was a ‘diplomat’. 

But del Burgo guessed it straight away, telling her: ‘You’re with Felipe of Bourbon.’ Letizia did not deny it, and that night she made a pact with del Burgo to transform their relationship into an enduring friendship.

Felipe had seen Letizia on national TV and a dinner party was hastily arranged with 16 guests so that he could meet ‘the girl he had fallen in love with’.

In another accusation, the book claims Letizia was pregnant at the time with a child by another man — journalist turned novelist, David Tejera. What’s more, the prince was completely unaware.

Ten days later, with the prince’s advances undeniable, Letizia made the decision to abort her baby.

The procedure (first alleged to have happened in a book written by Letizia’s cousin in 2013) took place at a clinic in Madrid on October 27, 2002.

Penafiel now claims it was her second abortion as she had one previously at the age of 19.

Penafiel writes: ‘When Felipe got engaged to Letizia he didn’t know about the abortion but, as the wedding neared, in a gesture of honesty, Letizia told him about it. And the most serious thing is that the king was in agreement with her that all trace of that abortion had to be erased.’

Queen Letizia, Telma Ortiz and Robert Gavin Bonnar pictured together

Spanish King Felipe VI and Queen Letizia  arrive for the official lunch of the Annual Meeting of the Cervantes Institute, at the Royal Palace of Aranjuez, Madrid, Spain

Surprisingly, del Burgo claims he was a key ‘adviser’ to Letizia when representatives of the royal family prepared a pre-nuptial agreement. He urged her to protect herself and not suffer the same public harassment that Princess Diana had endured after her divorce from Prince Charles.

As Penafiel writes: ‘Although it was clear from the first moment that Felipe and Letizia’s marriage was one of love, no loose ends could be left in the event of a possible divorce.

‘There was something Letizia was refusing to sign in the pre-nuptial agreement as it was drafted by the Palace advisers — the issue of the children should there be a separation.’

The book adds: ‘It was Jaime (del Burgo) who advised Letizia not to sign in the way it had been written, alleging she risked being treated like Lady Diana.

‘Felipe promised Letizia that in case the marriage folded, he would take care of her and respect her rights as a mother if they had descendants. The prince’s words were ‘I swear it’.’

Letizia ended up signing the agreement exactly as the Royal Household lawyers had drafted it because, as she admitted, ‘It is what it is, this is not just a fling.’

Days before the wedding ceremony, which was attended by royals from all over the world including the then-Prince Charles, del Burgo claims Letizia professed her enduring love for him in the luxurious and exclusive El Latigazo restaurant, close to the Zarzuela Palace. 

Letizia allegedly asked him to ‘never leave’ her, and demanded to know why del Burgo had never asked to marry her. He couldn’t find the words to reply.

Within days, Letizia would walk down the aisle in Almudena Cathedral in a Manuel Pertegaz gown, complete with 15-foot train, to marry another man.

Prince Felipe’s father, King Juan Carlos I, was opposed to the union, branding Letizia the ‘enemy within’ and expressing fears she would ‘destroy the monarchy’.

The book claims Felipe’s mother, Queen Sofia, ‘just cried’ when she heard her son defend his ‘commoner’ girlfriend, telling the King: ‘I marry her or I renounce my right to the throne.’

MADRID, SPAIN: Queen Letizia of Spain watchs a military parade after the solemn opening of the 15th legislature at the Spanish Parliament

Nonetheless, it was Queen Sofia who chose Letizia’s wedding gown with its famous stand-up collar.

Del Burgo says he and Letizia remained ‘friends and confidants’ from 2004 to 2010. But after Letizia had been married to Felipe for six years, she rekindled her romance with him. 

He recalls a scene in July 2010: ‘Lying in the same hammock, under the pool porch, facing each other, [Letizia] told me ‘I love you’. And I replied, ‘I love you’.

‘That same night our love relationship continued, interrupted years before, because love was always there since our first trip to Venice in 2002.’

Del Burgo continued: ‘That moment, in the hammock, was one of those in which life takes a turn.

‘We travelled to Cape Verde, to Greece on a cruise, the United States, to the English countryside, to Provence in France. She came to London, I went to Madrid.

‘For a year and a half we thought and took steps forward with the idea of being free, we dealt with the question of the divorce, the girls, we sought legal advice, we viewed a house in the neighbourhood of La Florida next to Zarzuela to live in while we were in Spain.

‘We considered New York as the best option in terms of a permanent residence. She proposed the idea that we would have a child via surrogacy in Los Angeles.’

But Queen Letizia — who gave birth to Leonor and Sofia in 2005 and 2007, respectively — broke off the affair in 2012 after 18 months, fearing her infidelities might be exposed.

Remarkably, that same year, del Burgo married Letizia’s own sister, Telma Ortiz. At their wedding in 2012, a succession of guests lined up to congratulate him.

Del Burgo is quoted in the book as saying: ‘When the guests congratulated us, Letizia’s turn came and, kissing me on the cheek, she whispered into my ear, ‘We’ll be together again’.’

Next year King Felipe VI and Queen Letizia celebrate their 20th wedding anniversary: two decades since the wedding that Penafiel perniciously claims Letizia described as ‘the deal of her life’.

Little is known about how the couple plan to celebrate the landmark. A representative of the Spanish royal family has said they have no comment to make about the allegations.

A gift of china is traditionally given to celebrate 20 years of marriage. Perhaps, after the furore and public dismay at these revelations, a delivery of fine china will be the only thing not broken in the historic House of Bourbon.