For a royal scandal with a dash of shock and awe, this week we look to Spain, where its former king has fled the country under a cloud of corruption allegations.

This is the same former king who was accused of trying it on with Princess Diana, and was reported to be quite the ladies’ man.

Juan Carlos, who ruled for 39 years from 1975 to 2014, has fled following a series of allegations he pocketed tens of millions of dollars from a Saudi Arabian deal in an offshore Swiss bank account.

He dropped the news to son and current rule King Felipe via a letter published this week.

King Felipe sent “his heartfelt respect and gratitude” to his father for the decision. Photo: Getty

Carlos said the “public repercussions that certain past events in my private life” was a key driver in his “well-considered decision to move away from Spain”.

The letter also stated Carlos’ decision was “guided by the conviction to provide the best service to Spaniards, its institutions and to you as King”.

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But critics suggest the 82-year-old’s motives for leaving are significantly more self-serving.

In addition to mounting public dissatisfaction with the monarchy, Carlos was facing a Supreme Court investigation and potential prosecution for his involvement in a lucrative high-speed Saudi rail project linking cities Mecca and Medina.

King Felipe has tried to distance himself from his father’s transgressions. Photo: Getty 

The investigation was set to determine whether or not the former king profited from the €6.7 billion ($11 billion) Saudi contract, which was awarded to a number of Spanish firms.

Spanish authorities are also investigating whether the rail deal is connected to a €65 million ($106.8 million) donation from 2008 that was made to a foundation linked to Carlos by the late Saudi king Abdullah.

Swiss authorities have joined the probe, following the discovery of undeclared funds in Switzerland, allegedly belonging to the ex-King.

Fall from grace

Carlos ascended the throne in November 1975, following the death of Spain’s fascist dictator Francisco Franco.

After a strong start bringing democracy to Spain, the former monarch eventually fell out of favour with the public.

No stranger to controversy, Carlos eventually abdicated in 2014, following a problematic elephant hunting trip during Spain’s financial crisis.

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The decision was made amid larger allegations of embezzlement directed at him, his daughter Princess Cristina and her husband Iñaki Urdangarin.

Despite praising his decisions to abdicate, and later leave Spain altogether, the current monarch, King Felipe, has been eager to distance himself from his father.

Once praised by his people, Carlos left the monarchy amid mounting criticism. Photo: Getty 

Earlier this year, King Felipe declared he would be forgoing his personal inheritance, and also scrapped his father’s annual €194,000 ($319,000) stipend.

Spanish Prime Minister Pedro Sánchez said the allegations of corruption were “unsettling”.

“It’s obvious that, collectively, Spaniards are hearing some unsettling reports that disturb all of us, and which disturb me too,” Mr Sánchez said in July.

“But I think there are some things worth mentioning in all this. First, that there are some media that aren’t looking the other way – on the contrary, they’re reporting all this.

“Second, there’s a justice system that’s taking action.

“Third – and this is something I’m grateful for – the royal house itself had distanced itself following these disturbing reports.”

From one royal to another

At the time of his abdication in 2014, the king took a swipe at Queen Elizabeth, comparing his son to his British royal counterpart.

“We do not want my son to wither waiting like Prince Charles,” Carlos said.

But that wasn’t the only time Carlos took aim at the UK royal family.

The Spanish royals hosted Princess Diana and Prince Charles in Mallorca in the mid-1980s, where it is speculated Carlos made a “tactile” pass at the people’s princess.

The king was some times referred to, and the two royal families spent some time together on holidays.

Royal all-stars: The British royal family holidayed with the Spanish monarchs in 1987. Photo Getty. 

According to a memoir by her bodyguard Ken Wharfe, Diana is quoted saying the Spanish King had made advances towards her.

“Juan Carlos is frightfully charming but, you know … a little too attentive. I know it’s absurd, but I’m sure the King fancies me,” Lady Di said.

On this trip, Prince Charles and Diana were accompanied by their then toddlers, Prince Harry and Prince William.