Princess Corinna zu Sayn-Wittgenstein’s lawyers, Kobre & Kim, have written to Home Secretary Priti Patel and Foreign Secretary Dominic Raab to warn them of a potential diplomatic row

It was strange enough that, in the small hours of June 2017, an unknown intruder found his way across the many dark acres of the Chyknell Hall Estate in Shropshire, past the dogs, the alarms and security men without detection.

What the housekeeper found when daylight broke was stranger still.

Nothing had been taken.

Nothing was even broken or disturbed, save for this: a perfect disc of glass the size of a side plate had somehow been removed from a first-floor bedroom window pane and the cold morning air was blowing in.

The police were mystified, yet for the glamorous mistress of Chyknell Hall, the meaning was all-too-clear.

The attack on her country home was a warning, the latest act in what she describes as an eight-year campaign of intimidation combining high finance, mercenaries, death threats, royalty – and the shadowy forces of a foreign state acting with impunity on British soil.

Today, Princess Corinna zu Sayn-Wittgenstein is poised to launch an explosive case in the High Court alleging that the Spanish state and its security services have, in legal language, conspired to ‘injure’ her.

Or that, in common parlance, they are attempting to destroy her life.

The 55-year-old businesswoman, a frequent guest at Royal events and a former lover of the now retired King of Spain, Juan Carlos, will tell the court that:

The Spanish intelligence service, CNI, has spent millions on a campaign of harassment in the apparent belief that she possesses state secrets;

She has been under constant hostile surveillance from Spanish agents, whether in the countryside, at home in London or abroad;

Her phones and computers have been hacked and disabled along with other electronic equipment, including the panic button in her bedroom;

A sustained attempt has been made to brainwash her children into believing she was corrupt;

She has suffered a campaign of libellous ‘fake news’ coverage on the internet;

And that this extraordinary catalogue of events began with the public exposure of her five-year relationship with Juan Carlos, who flew into London for a secret visit just last year.

It is with huge reluctance that she is talking in public but, with the abuse intensifying and her business suffering, Corinna says she is desperate to put a stop to the intimidation she says has been directed towards her.

The High Court case will be led by James Lewis QC, who is currently prosecuting Julian Assange on behalf of the Crown.

Corinna’s lawyers, Kobre & Kim, have written to Home Secretary Priti Patel and Foreign Secretary Dominic Raab to warn them of a potential diplomatic row.

‘Discretion has been a watchword throughout my life with my family and my business,’ Corinna told The Mail on Sunday.

‘After eight years of abuse, which has also targeted my children, and given there is no end in sight, I reluctantly find myself with no other option but to pursue legal action.’

Princess Corinna zu Sayn-Wittgenstein is poised to launch an explosive case in the High Court alleging that the Spanish state and its security services have, in legal language, conspired to ‘injure’ her. Or that, in common parlance, they are attempting to destroy her life

Even today, she might seem to have an enviable life. There are several homes, including the £6 million Chyknell Hall Estate, which comes complete with cottages and a cricket green amid its 200 acres; a Belgravia apartment; and a rented property in Monaco.

Twice-divorced Corinna became a princess through her second marriage, to German aristocrat Prince Casimir zu Sayn-Wittgenstein-Sayn.

She is a long-time friend of Lord Snowdon, Princess Margaret’s son, has been a regular at Prince Charles’s philanthropic occasions and was honoured at Buckingham Palace for her efforts in supporting the Duke of Edinburgh Awards Foundation.

To say she is well-connected is a gross understatement.

In the world of international finance, Corinna is known for brokering deals between major corporations and is said to include several heads of state in her contacts book.

Prince Albert of Monaco was the guest of honour at Harry’s Bar in London for her 40th birthday dinner – other guests that night included members of the Astor, Spencer-Churchill, Goldsmith, Versace and Swarovski families.

But this glamorous way of life came to a halt after it emerged she had conducted a five-year relationship with the married King of Spain, Juan Carlos.

And from that moment on, she says, the Spanish secret service trained its sights on her.

The affair had come to light in 2012 when – with the relationship already over – it was revealed that Corinna and the king had been on safari to Botswana along with her son.

The hunting trip scandalised Spain, which at the time was going through a recession – the more so as it was reported that the king had shot and killed an elephant.

Two years later, Juan Carlos – now 82 and styled King Emeritus – stepped aside in favour of his son Felipe VI.

The first sign that something was wrong came in 2012, soon after the affair was revealed, when she found herself trailed by a team of Spanish-speaking men while on business in Brazil.

But it was later that same year, when her Monaco apartment was occupied for more than a month by French and Polish mercenaries, that Corinna knew she had a serious problem.

There are several homes, including the £6 million Chyknell Hall Estate, which comes complete with cottages and a cricket green amid its 200 acres; a Belgravia apartment; and a rented property in Monaco

She was informed by the Spanish intelligence services that the mercenaries – employed through a Monagesque security company – were there for her protection.

But, as she will tell the High Court, she believes the real objective was to occupy her flat and remove documents.

‘I was in constant danger,’ she told this newspaper. ‘At first, I thought these men were going to throw me over the balcony.

‘The fact that mercenaries can occupy an apartment in Monaco for over a month and then Spanish operatives can enter and steal documents, with impunity, raises very serious questions about the principality.’

Corinna’s executive assistant, Melissa Holloway, who was there at the time, confirmed her story: ‘They looked like paramilitaries and immediately took full control of the property,’ she said.

‘The stress was overwhelming. They were clearly not there to protect us.’

In June that same year, Corinna says she was confronted in her room at The Connaught hotel in London by the CNI which – in her interpretation, at least – threatened her life.

‘Following the intelligence service’s intrusion into my hotel room I was terrified, particularly when they made a threat against my life and the lives of my children by saying they could not guarantee our physical safety,’ she said.

‘They were adamant that I stay silent. They sent me an email using a pseudonym explaining that if I were to talk to the media, it would be devastating for my “image”. I took this to mean that if I did not fully co-operate, my reputation would be destroyed. In fact, this threat was carried through very successfully.’

The High Court will be told that when she travelled to Switzerland to visit her son at boarding school, she found that someone had placed a book about the death of Princess Diana (who was herself rumoured to have had an affair with Juan Carlos) on her coffee table.

The next day, she received a phone call from an unknown number and a voice said in Spanish: ‘There are many tunnels between Monaco and Nice.’

Was she, too, destined to die in a road tunnel?

Meanwhile, Corinna found hundreds of fake news articles appearing online which falsely accused her, among other things, of stealing money from Spain and Spanish companies and selling 250 Spanish tanks to Saudi Arabia – allegations she describes as ludicrous.

It is true, she says, that the king had made a generous financial endowment for her and her son in 2012, but she says this is fully documented and that the gift was checked thoroughly before she agreed to accept it.

Two books were published portraying her as a corrupt social climber who had bewitched the King Emeritus.

‘My legal team wrote to the publisher and they were removed from circulation,’ said Corinna.

‘All those who knowingly partook in this abuse will face justice. The fact that, in a civilised democracy, part of the European Union, serious news outlets can be used as a platform for the kind of fake news that doesn’t even withstand the most rudimentary scrutiny is profoundly shocking.’

From the beginning of what she describes as the campaign against her, Corinna and her staff – including several British citizens – have found their phones and computers tampered with.

There have been constant cyber attacks on her house in Belgravia, including the remote disabling of the panic button in her bedroom.

Today Corinna says she’s routinely followed in London, and that her home was at one point put under special police protection.

Then, in 2017, came the mysterious break-in at her Regency mansion, Chyknell Hall.

Adam Crookshank, a former officer in the British Army and Corinna’s chief of staff, said: ‘It is astonishing that somebody would be able to cut a perfect hole in Corinna’s bedroom window.

‘It shows a high level of competence, not only to execute it, but to know which bedroom was hers.’

On March 5 last year, Corinna’s legal team wrote to the head of the Spanish royal household informing them of the alleged abuse, requesting a meeting and talking for the first time about legal action.

There was no response, but several days later the king called her from his satellite phone and made an urgent request for an appointment to see her in London.

On Saturday, March 16, he flew to London on a private jet and met Corinna and her son, Alexander. The British authorities were not informed.

Alexander, 17, confirmed that the meeting had taken place and said: ‘I cannot discuss the details of this private meeting except to say the King Emeritus was very preoccupied with the subject of media interest.’

What could motivate agents of the Spanish state to behave in such a way? Corinna believes it is the result of political infighting within Spain, combined with a suspicion that she knows more than she actually does from her time with Juan Carlos – plus a wish to keep her firmly under control.

‘I believe they want me out of the way,’ she said. ‘It is quite obvious that they fell I am a threat.’

Princess Corinna zu Sayn-Wittgenstein is pictured with Prince Charles and Bob Colacello. According to her lawyer, Robin Rathmell, legal counsel at Kobre & Kim, the case is of the utmost importance

Far-fetched as her account might seem, it is a story that some extremely serious people are prepared to believe.

James Watt, a former British ambassador to Lebanon and Egypt, is one of her advisers on the case.

He said: ‘An extraordinary campaign of character assassination and psychological pressure was mounted and has been driven with obsessive persistence for eight years.

‘It must have involved a major commitment of resources by the Spanish secret services.’

In a sworn affidavit, which will form part of the High Court evidence, Jose Villarejo, a former commissioner with the national Spanish police, said: ‘I can only say there are about 120 agents in charge of actions referring to the so-called incidents with the monarchy. Corinna was fully controlled, fully monitored by a team of the CNI.’

Corinna’s legal team has written to MI5 and MI6. The Foreign Office and Buckingham Palace have also been informed.

So far, she says, neither the Spanish embassy in London nor the royal household in Madrid have engaged with her or her legal team.

But the Spanish are likely to deny her claims and mount a vigorous legal defence.

According to her lawyer, Robin Rathmell, legal counsel at Kobre & Kim, the case is of the utmost importance.

‘The fact that people from a foreign intelligence service flew to London unannounced in order to threaten a private citizen in her hotel room is astonishing and demands a serious investigation,’ he said.

‘All reasonable attempts to resolve the situation out of court have failed.

‘Our client has no choice but to pursue a formal legal path. This case will expose an extraordinary abuse of power across multiple jurisdictions.’