A former king of Spain has begun an appeal bid after losing a High Court fight with an ex-lover.

Danish businesswoman Corinna zu Sayn-Wittgenstein-Sayn is taking legal action against Juan Carlos, who abdicated in 2014, seeking damages for personal injury.

The 57-year-old alleges he caused her “great mental pain” by spying on and harassing her.

Juan Carlos, 84, denies wrongdoing and disputes the claims made against him.

Lawyers representing Juan Carlos argued that he is “entitled to immunity from the jurisdiction of the English courts in his capacity as a senior member of the Spanish royal family”.

But a High Court judge disagreed.

Mr Justice Nicklin ruled earlier this year that the claim could go ahead in England.

Two Court of Appeal judges in July allowed Juan Carlos to challenge some of the conclusions reached by Mr Justice Nicklin.

Three appeal judges – Lady Justice King, Lady Justice Simler and Lord Justice Popplewell – began considering detailed arguments at a Court of Appeal hearing in London on Tuesday.

The hearing in due to end on Tuesday afternoon and the judges are expected to deliver a ruling later this year.

Barrister James Lewis KC, who is leading Ms zu Sayn-Wittgenstein-Sayn’s legal team, told the three appeal judges that Juan Carlos’s challenge should be dismissed.

“The issue raised in this appeal is whether (Juan Carlos) is entitled to state immunity in respect of those elements of (Ms zu Sayn-Wittgenstein-Sayn’s) claim for harassment that pre-date his abdication on 18 June 2014,” he said in a written case outline.

“These acts include those of (Juan Carlos’s) loyal friends with intelligence and surveillance agents as his agents.”

He added: “(Ms zu Sayn-Wittgenstein-Sayn’s) case against (Juan Carlos) in relation to post-abdication allegations of harassment is currently stayed pending determination of this appeal.”

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

They have been told that Ms zu Sayn-Wittgenstein-Sayn, who lives in England and has a home in Shropshire, wants an “injunction and damages” resulting from “a continuous and ongoing campaign of harassment” against her, “commenced” by (Juan Carlos) from 2012, following the “break-up of an intimate romantic relationship” and her “refusal to let (Juan Carlos) use a financial sum irrevocably gifted to her, or to return other gifts”.

Lawyers representing her have alleged to judges that conduct “includes (the former king) or his agents smearing her and her business in the media, following her, entering her home in Shropshire, and bugging her homes and electronic devices”.

Mr Justice Nicklin rejected the argument that, despite his abdication, Juan Carlos remains a “sovereign” and is entitled to personal immunity under the State Immunity Act 1978.

He also said Juan Carlos is not a member of the current king’s household within the meaning of that Act.

Mr Justice Nicklin said the former king’s position under the Spanish constitution is “entirely honorary” and provides him “no continuing role”.

Timothy Otty KC, who is leading Juan Carlos’s legal team, told judges in a written argument: “His Majesty… emphasises at the outset that he considers this claim to be vexatious.

“He emphatically denies that he engaged in, or directed, any harassment of the respondent whatever, and he rejects her allegations to the contrary as untrue and inconsistent with previous public statements made by her.

“The allegations also involve an alleged abuse of power wholly inconsistent with His Majesty’s important role in the transition of Spain to a successful parliamentary democracy and his long period of service as sovereign.”