Former King of Spain's ex-lover 'has book claiming MI5 involved in Princess Diana's death'

An ex-lover of a former king of Spain has alleged that "intruders" left a book at her apartment about the "involvement of the British and US intelligence agencies" in the death of Princess Diana.

Corinna zu Sayn-Wittgenstein-Sayn, who is taking legal action against Juan Carlos, claimed "an operation" was carried out by Spanish intelligence agents at her home in Switzerland, a Court of Appeal hearing in London heard today.

The businesswoman also alleged that she received a "follow-up telephone call" from an "unknown person" who made an "allusion" to the manner in which Diana died, a barrister representing Juan Carlos said.

Juan Carlos, 84, who abdicated in 2014, has begun an appeal bid after losing a High Court fight with the 57-year-old.

Ms zu Sayn-Wittgenstein-Sayn is taking legal action against Juan Carlos, seeking damages for personal injury.

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Juan Carlos and Corinna zu Sayn-Wittgenstein-Sayn in Germany in 2006 ( Image: Action Press/REX/Shutterstock)

She alleges he caused her "great mental pain" by spying on and harassing her.

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

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