An ex-lover of a former Spanish king has told a London judge that she was the victim of a “sinister” campaign by an “exceptionally ruthless” man.

Danish businesswoman Corinna zu Sayn-Wittgenstein-Sayn, 58, who has made a harassment claim against Juan Carlos, 85, and wants damages of more than £126 million, said the impact on her life had been “catastrophic”.

Ms zu Sayn-Wittgenstein-Sayn, who has homes in England, has sued Juan Carlos, 85, who abdicated in 2014, and wants damages for personal injury.

She alleges that he caused her “great mental pain” by harassing her.

He has denied harassment.

Mrs Justice Collins Rice is considering the latest stage of the dispute at a High Court hearing in the Royal Courts of Justice complex in central London.

The hearing is expected to end later this week.

Lawyers representing Juan Carlos have asked her to dismiss Ms zu Sayn-Wittgenstein-Sayn’s claim.

She says the case should continue.

A barrister leading Ms zu Sayn-Wittgenstein-Sayn’s legal team on Wednesday said Juan Carlos had begun a “sinister campaign to control her”.

Jonathan Caplan KC told the judge how Ms zu Sayn-Wittgenstein-Sayn had said in a written witness statement: “I think he is exceptionally ruthless.”

She had described the impact on her life as “catastrophic”.

Mr Caplan argued that a trial was “inevitable”.

“There are a series of substantial issues of fact here between the parties,” he told the judge.

“They cannot be decided without hearing evidence.”

He added: “The applications by the defendant are misconceived.”

I think he is exceptionally ruthless

A barrister representing Juan Carlos has told the judge that Ms zu Sayn-Wittgenstein-Sayn’s case has “no realistic” prospect of success.

Adam Wolanski KC said evidence “simply did not disclose a viable case”.

He Juan Carlos “emphatically denies ever having harassed the claimant”.

A number of other judges have overseen earlier hearings in the litigation.

Judges have been told that Juan Carlos ruled from 1975 until his abdication in 2014 and the succession of his son, King Felipe VI.

They have heard that Ms zu Sayn-Wittgenstein-Sayn is Danish, lived in Monaco between 2008 and 2019, and has homes in London and Shropshire.

Mr Wolanski also wants Mrs Justice Collins Rice to rule that judges in England have “no jurisdiction” to consider some of the allegations.

Juan Carlos won the last round of the case.

Another High Court judge – Mr Justice Nicklin – had ruled that claims could be considered at a trial in England.

But in December, Juan Carlos won an appeal after challenging some of Mr Justice Nicklin’s conclusions.

Court of Appeal judges in London concluded that “the pre-abdication conduct alleged” was “immune from the jurisdiction of the courts of this country”.

A lawyer representing Ms zu Sayn-Wittgenstein-Sayn said in December that the appeal court ruling would not affect claims she made about Juan Carlos’s behaviour after his abdication.