59-year-old Corinna zu Sayn-Wittgenstein-Sayn had accused the former King of Spain of a campaign of harrassment following their split.
The former King of Spain, Juan Carlos, has suggested he may return to public life after having avoided a legal case brought by his ex-mistress, who was suing him in London for an apparent campaign of harassment.
Corinna zu Sayn-Wittgenstein-Sayn attempted to claim €145m for the psychological damage she believes she suffered.
In October 2020, she initiated proceedings for harassment in London, where she lived.
But in her written judgement, Judge Rowena Collins Rice concluded that "the High Court of England and Wales does not have jurisdiction to judge" such proceedings.
The judge also notably underlined that the complainant has “not sufficiently established” that the facts giving rise to her request occurred in England.
Also known as Corinna Larsen, the German businesswoman, 59, claims that from 2012, she was spied on and harassed for eight years on the orders of the former monarch.
She allegedly suffered threats, as did her children, according to the complaint.
Juan Carlos allegedly demanded that she return gifts, such as works of art, jewellery and money amounting to some €65 million.
Their relationship became public in 2012 when the then monarch broke a hip while on vacation in Botswana. The affair, revealed against a backdrop of record unemployment in Spain, provoked widespread anger in the country.
Juan Carlos, who abdicated the throne in 2014 following a series of scandals, welcomed the judgement, saying it "unsurprisingly confirms his innocence".
He went on to say the decision "reestablishes the necessary conditions for new public appearances".
In contrast, Corinna zu Sayn-Wittgenstein-Sayn said she was “deeply disappointed” by the ruling, adding that it was “disheartening to see that victims of harassment often struggle to find justice in our legal system".
Prior to the court’s decision, UK judges ruled last December that she could not sue Juan Carlos over allegations relating to the time he had served as king - as he had immunity as sovereign.
Having assumed the position of head of state in 1975, after the death of the dictator Franco who had appointed him to be his successor, Juan Carlos was praised for decades for having overseen the return of democracy to Spain.
His popularity collapsed after personal scandals and revelations about his lavish lifestyle in Spain from 2012 and he abdicated in 2014 in favour of his son Felipe VI.